This is a fascinating thread for me, but also frustrating because I was on Ian's site last week and this week it is gone. (All the domains associated with him are now down. Does anyone know any contact details for whomever used to maintain the sites?)
Doubly frustrating is the fact that I have only just signed up here, and just begun to get back into pottery after a long hiatus. In the meantime I will find his books and begin to experiment, as I am trying to find options for a difficult-to-glaze black stoneware body.
I made a spreadsheet on Google that works out each glaze. What it doesn't do is input the right silica and kaolin values as I wanted to use it to create grids outside those constraints. Right now I think it does have the right values in to do a true currie test and you can mess around with the flux ratio between themselves. Will double check when I have my glaze book.
Fill in the blue boxes and the rest is worked out. It has a table of grams of glaze per test and a table of how many ml of each glaze you add. Then another of each 35 glaze.
Save your own copy as backup because it is free to edit by anybody with the link. Also a few other things saved on my laptop that I can post later.
I found stretching elements the hardest part, replacing it into the kiln is easy. Skutt probably prestretch your elements anyway.
How are elements rated to a cone? I thought it was more down to the insulation as every element is that Kanthal A1 blend. I thought the thickness was down to the power needed so resistance needed, this balanced with having an element thick enough to withstand lots of firings.