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to maximize the number of tests a test tile provides is it ok to test glazes both on the front and the back of standing tiles?   or will the chemistry go through the clay and interfere with the other side?  
I read an instance where a glaze should not be used on a pot if that pot was glazed on the inside as well.?  is this a common issue or just a rare occurrence specific to one particular type of glaze?  

I haven't seen that, and would be interested if you have a ref.
But I have seen occasional references to needing to let the pot dry sufficiently between glazing one surface and the other.
... this seems to be more of an issue with dipped glazes than painted ones.

"...Is it ok to test glazes both on the front and the back of standing tiles?"
Good question!
My first thought was - it makes for the tests to mimic the intended applications - then, huh! ...ok, I'm going to think about that a while*...
You might try side by side comparisons, set of tiles with glaze on one side only, another set with different glazes on both sides?
It's possible that glazes that have dissolved materials could influence the other side...
I liner glaze almost everything but have never set up test tiles with liner on one side and "outside" glaze on the other side; just dipping about halfway in at a forty-five degree angle, where second dip overlaps in the middle as Bill alluded to.
My test tiles check a new glaze against clays I'm using, else glazes I'm using against new clay, looking for:
   fit - no crazing or shivering
   coverage - no crawling
   color
   fizzing/bubbles
   pinholes
   how it works applied thinly, thickly
   ...
*I pour in and out the ware interiors, and dip the exterior, with a full dry in between.
So, my test tiles don't reflect how I'm glazing wares, with liner on one side and color on the other.
When I do a set of test tiles, almost always I'll also fire a small ware or two of the test case(s) that are liner glazed.
 

It does look like a crawl/reticulated glaze but I think the tricky part would be how they got it to stay on the pot on the undercut vertical surfaces. 
100 Grand maybe?

Could be a Dry Lakes glaze - there are several available that have super heavy, thick textures in various colors just like this.  Such as this one:  Luguna Dry Lake Blue
There are also several bead and pebble glazes out there that crackle and crawl and due to the rounded edges I suspect that more than the Dry Lakes - such as this Ritual Glaze Bead and here are some Brain Coral Crawl Glaze Recipes
Here's another one though a little different look to it shown on Pinterest Crawling Glaze
So maybe that will be helpful to you.  I have used this kind of glaze heavily on stoneware before and it's HUGELY FREAKING FUN.  But sometimes it's pricy too.  You can also try layering it on thickly and doing multiple fires to see how it progresses!
I imagine if you texture your ceramic body first and then apply this you can really push it further and that may be what he did.  Good luck!

Something like this reminds me a bit of Robert Sperry, along with some really gnarly shinos in historical Japanese pottery. Granted, they’re two different things. I was told many years ago Sperry used slip on top of glaze for his dramatic effects, I can only imagine it was the product of serious experimentation. I’m afraid that’s all I can offer.
https://www.bellevuearts.org/exhibitions/past/robert-sperry

It’s probably a combination of slips/engobes/crawl glazes. It looks like there’s a lot of layers of different things, and without knowing who the artist is or anything about the process, that’s as much as I can guess. 

Hulk gives good advice, however, there is nothing that says you have to fire on a kiln shelf. You run the risk of the glaze running onto the kiln floor, but if that's a problem you can live with, firing on the floor is no problem. Does your glaze run?
A kiln shelf helps to distribute weight if your piece is heavy. (If your piece is heavy it might stress the bricks if fired without a shelf.)
You might also check to see how much your kiln lid sags.  (If at all?) This too affects how tall you can fire.
Its been my experience that most clays shrink about 5% from wet to bone dry. (At least my cone 6 slip cast porcelain does.) Doing a little test will help you determine the amount of shrinkage of your clay.
As Hulk suggests leaving 1/4" space between the top of the piece and the kiln lid is good. I might make it 1/2" if I'm unsure?

With a base shelf and half inch risers underneath it, you'd be down to 25.5" to start (given 1" shelf).
My experience* says leave a smidge of room for expansion.
Although everything gets hot and therefore expands, perhaps not all at the same rate, so leave a quarter inch, at least?
Mainly to avoid touching and therefore melting together, also 
   a) extra space between wares and the elements to reduce any spitting of bits/droplets onto the elements, and
   b) extra space between wares where reducing fuming** is a concern.
Use a tape measure or ruler to get the available space.
If you're throwing/making to the available vertical, the subsequent clay shrinkage should leave plenty of wiggle room...
Check back later for more input from other Forum members!
 
*I'm typically firing three to five levels in my 27" kiln. Sometimes I leave just a quarter inch from top of the ware to the next shelf (or the lid); so far, a-ok.
**I like how my red glaze picks up some blue/cobalt. The chrome seems to get around as well.

some of my experience
Thickness will help, but you may be able to design around it depending on what is collapsing. Larger diameters if you will instead of tall and  slender can enhance the strength.  Horizontal shoulders collapse but gradual thickening inside can allow the force to distribute down into the sidewall clay on axis rather than a cantilever shoulder. So when practical select thickening of areas is definitely a thing for me.

My BFA professor was a sculptor, her work was around 4-5 feet tall and probably averaged an inch thick. She used an Imco sulpture clay, it was pretty groggy. Also fired very slowly. Another thing I've seen is people building reinforcing structure inside the sculpture, extra walls where support is needed. 

The plaster itself should dry the surface of the clay enough that it will release. If it's not releasing quickly enough, then dust some corn starch on the mold or the clay before pressing it. I would not use any sort of liquid on the plaster, as it will just soak in and ruin the porosity of the plaster.

You might refer to it as a "thermally insulated oven" or "chamber"?
Presuming you're in New York, you might google "NY Building Code kilns" and see what you get. (Just change the state if you're not in NY.)
My state, Minnesota, publishes its building code on a public domain website. Its the full code, so it takes patience to look through the whole thing, but if you're lucky it's indexed well so you can find it sooner than later.
 
 
 

Did you use the term 'ceramic kiln'? Did you explain what it is? That term may not mean anything to them. I'm betting that if you said 'pottery kiln' they would get it, because most people have had some sort of experience with pottery during their childhood or college years. You might just have to explain it to them, and maybe give them some links to the kiln manufacturer's website. Which insurance company? The town will want to inspect it, and if they don't know anything about it they will generally defer to the manufacturer's recommendations for installation.

Good question!
I don't have an answer, mainly just wanted to give your thread a "bump"...
...and suggest trying your insurance company again, as you might get another person on the line.
As for the building department, my guess would be that permits and inspections for any alterations/additions (electrical, plumbing, etc.) would be of interest to them.
Meanwhile, for your consideration:
  new smoke and CO detectors;
  functional primary and secondary ventilation*;
  correct wiring, including proper fusing/breakers;
  commitment to attending throughout each firing - the entire time the kiln is over 451°F;
  placing new/serviceable fire extinguishers at the kiln and all approaches to the kiln.
*primary: powered kiln vent that pulls a tiny stream of superheated kiln atmosphere from the bottom of the kiln and pushes it outside via a dedicated vent
secondary: overhead system that evacuates hundreds of cubic feet per minute via dedicated venting
important note for both: provision for "make up air" is critical - air must be allowed "in" to make up for what is being pushed "out"
Hope that helps.

If you make a very thick slip, then make it desired fluidity by using Darvan or sodium silicate, just drop by drop, then with less water involved there will be less shrinkage. Too much darvan will make it go clumpy.
Also, spray your sculpture with a fine mist of water prior to adding slip to it will help also.

I don't vent either of my test kilns,   I think they are too small.   I have put a piece of shelving under the edge of the lid during a bisque firing.    My old AIM kiln had a large peep hole that the fumes could get out.   My new Paragon is sealed up,  no peep holes.  I remove the piece of shelf when the fumes are gone.  a window is behind the test kiln.   I have a small manual kiln that I can easily fill and do a bisque firing so I try to stick to glaze firings in the test kilns.    Denice

I fired a big Skutt in a basement like that for 13 years,   I had some ventilation but not enough,  you have windows so you could probably run a vent hose out it.   My ceiling was tongue and groove boards  and my floor and walls were cement.   You could always put up some cement board if the ceiling worries you.   The Skutt was in the same area as the breaker box,  I had a electrician put in the correct breaker, wire and outlet.   It was a old house and some of it still had knob and tube wiring.   Make sure you buy a kiln that comes in sections,  much easier to move.  On days the kiln was fuming more than my ventilation set up could handle I would stay out of the basement.   I don't think there is a system that removes all of the fumes.  My kilns are in a separate room  with a Skutt dual vent system,  a window and a ceiling exhaust.  Sometimes I can still smell fumes,  I can shut the door or leave the room.    Denice

Pretty clear you’re need an outdoor solution. It’s likely to solve more problems than it creates. An enclosure is doable, not rocket science. You will need good casters and a very smooth surface to roll that kiln. Kiln fires in open air, is retreated to its kennel/shelter when cool. With enough space around it elaborate leaf catching schemes may not be necessary. A hose is necessary. It’s gotta stay out of the weather when not in use. 
 
 

I bought a new Paragon Caldera XL last year.   My old test AIM test  kiln was in need of repair,   I was wanting to jump into the world of computerized firing.  It  has a Genisis controller and very tightly built with three inch bricks.   The three inch brick is very important,  my AIM had two inch brick that  cooled down way to fast.  I would try to slow it down manually,  it was very difficult to do.   I never felt like my test were totally accurate,  the glazes always looked different when they came out of a large firing.  The Genisis controller is also easy to use,  I believe the Caldera takes a 15amp outlet.   You could fire two mugs in it.  You may have to find a smaller test kiln with thick walls for a 120v outlet   Firing a test glaze fast could produce different results  than a big standard firing.   The Genisis  glaze program  is hours slower than the program I fired manually.   My L&L has the same controller so I just let it do it thing.    Denice

I believe the image in the first post is a work by Yō Akiyama and is from his work using stoneware, heat and peeling off layers of clay to achieve the cracks.  If you search his name you can find many examples of his work.
From this Wikipedia link:
"Akiyama developed and fine-tuned the latter technique in the 1980s while experimenting with the feasibility of peeling the outer skin off a ball of clay, in the same way that one might peel a fruit. To achieve this, he heated a ball of clay with a gas burner, creating a shape with a soft center and a hard, outer shell. Since that first experiment, Akiyama has refined his technique and manipulated this template to create a multitude of cracks and chasms on the surface of his pieces, in some cases completely inverting the shape."
 
 

A kiln that's appropriate for the target temperature(s), that's one consideration, e.g., if you're working in midrange (Cone 5/6), a kiln rated to Cone 10 will last a good long while.
If you are working at the upper limit/rating of your kiln, having to replace the elements will come much faster.
For your testing, following a firing profile (time and temperature) that's similar to your big/production/main kiln is another consideration. A test/small kiln with a controller makes that much easier, otherwise you're having to hover and flip the switches on and off to replicate the firing profile...
Hope that helps!
...mainly, just wanted to "bump" your thread so you might get some responses...

Sand or other temper like grog, chicken grit, large mesh feldspar, etc will indeed make a clay body less plastic.
As to the clay body pictured, I think the colour has less to do with the underlying material and more to do with how it was fired. If I had to guess, I’d say it was pit fired. That’s if it’s clay at all. 

Cracking can have a lot of reasons. If you find your reclaim is cracking more than fresh clay and all other forms of user error have been eliminated as possibilities, there’s 2 possibilities that come to my mind.
First, it could be that the reclaim has more throwing slop/fine particles in it. If there’s no trimmings or dry bits added to it, or you’re just drying the throwing bucket leftovers on the plaster wedging table overnight, you wind up with all the stuff that is plastic, but also shrinks a lot. If this is the case, save your throwing slop to add to larger batches of reclaim. If you don’t wind up with a whole lot of reclaim, you can repurpose it as decorating or casting slip. I know a lot of us feel strongly about waste, but it is ok to discard some in the trash if you really don’t have another use for it.
The other possibility (and I experience this with Plainsman M390) is that it may be a clay body that really needs to be slurry mixed to get useable reclaim. Some clays have a diverse particle mix, and if they’re not blended well, you wind up with issues. 
 

There are a myriad of reasons pieces can crack. Forming methods, trimming methods, drying methods, firing methods, glaze reasons, cooling methods and so forth. The go to resource for tracking down and determining why a piece cracked is Frank and Janet Hamer's book The Potter's Dictionary of Materials and Techniques. It is well worth purchasing and comes highly recommended by many people. You can see a snippet of the book and the relevant section on cracks in the link below.
There are over 30 scenarios for cracks.
https://books.google.ca/books?id=TApnGTVLwxAC&pg=PA86&lpg=PA86&dq=hamer+and+hamer+cracks&source=bl&ots=inS6KQPb4N&sig=ACfU3U3-WW9HznLwIEytHMyGanL2bpymZA&hl=en&sa=X&ved=2ahUKEwiG1JCB0KPgAhWyPH0KHX7EBo4Q6AEwB3oECAcQAQ#v=onepage&q=hamer and hamer cracks&f=false