liambesaw

I used a cone higher in my kiln for bisque, but not for glaze firing. You will need to check in on your cone packs towards the end of firing until you know when you can turn it off. A kiln sitter is not a replacement for monitoring a manual kiln. Once you know what your kiln will do you can rely more on the kiln sitter, but really you should be monitoring a cone pack

Id put the fiber on the outside! Not sure how much gas firing with a fiber kiln you've done, I mean the stuff is a modern miracle, no doubt... But it's also a real son of a gun. Brush your arm against it while you're loading? Enjoy the itches for the next hour! Oh, you brushed it ever so slightly and it came apart a bit? Time to pin it down again or suffer the wrath! Nothing is quite as disturbing as pulling bits of insulating fiber out of a glazed pot. Ugh. As you can likely tell, I fired in a fully fiber kiln for a year, and while I learned a lot and it was an adventure, I was secretly plotting a real kiln in the meantime. Fiber is cool and all (heh), but I keep it as far away from me and my pots as possible now. Bricks are much better, if you want to seal gaps in the brick junction, use a nice refractory cement, any pottery supply will have buckets for an unreasonable price.

Here in the US it's under 30 a gallon

Yes! A lot of our oxides are volatile at the temps we fire to. If a glaze, clay or slip has some fluorine in it, it will create hydrofluoric acid vapor that will etch glass even. The fumes from firing are pretty undeniably the most hazardous thing we will experience as potters.

My kiln is outdoors, I do not vent it for obvious reasons

I think it's just because plaster is very cheap and very easy to turn.

Maybe somewhere between soaked and dry would be best. I'd imagine a CNC mill would probably have a hard time clearing soaked plaster

You need to vent outdoors, a fart fan won't do anything for that. You need a kiln vent.

It's not bone dry plaster, at least that I've seen. It looks like it comes off in chunks and settles fast. Plaster also has no silica and doesn't pose the same long term risks that something like clay would.

Turning plaster on the lathe for masters is definitely a thing! More of a European thing I think, but I've seen lots of videos of it

You can add a controller to any kiln That said, if you're not comfortable with electronics, you might find it easier to hire a kiln tech to do it for you.

There are plenty of free options. I use Wave. I don't use any of the paid add-ons like payroll with them so it's 100% free

Not without stilting it. Even then I don't suggest it. You can order some progressively finer diamond disks from somewhere like Amazon and just polish the bottoms with those. It makes a smooth shiny surface.

Sole proprietorship, which needs to be licensed here in Washington

It could be because their online monthly version is cheaper and he was trying to save you money! The single user one is only 7 dollars a month which beats craftybase too