...this is really really helpful, and sometimes I absorb and remember things better when I type them up myself. So! I really am studying.
I created this table to help me remember the limit formulas - the range of ratios of flux, alumina and silica - for glossy, satin, or stony surfaces at ^6 and ^10. Remember these are ratios of molecule counts - we still haven't gotten to how they translate into percentages by weight, yet:
This is a simpler version of the table that Professor Cushing presents, which includes proportion ranges of specific fluxes, and of boron, an alternative low-temperature glassformer (if I am understanding that correctly.) Just this alone is (well, will be) tremendously helpful.
Once I get the translation part down, I'll only have to compare a glaze to this table to know if it has the appropriate proportions of silica and alumina to flux to work at my given cone level, and not be too soft or too viscous. There is great overlap in the percentages, because much depends on which specific fluxes are used, and because the categories are pretty broad: "Satin," for example, could describe a waxy shine or an eggshell matte.
Anyway, back to the book. Still a lot to learn! Hope this is helpful for someone out there in TV land.