What charts are these? I have no charts that tell me things like this
Beautiful glaze, would love to see one of your mugs with it on.
Glaze formula limit charts. They show the acceptable limits for each part of a glaze in the unity formula. If the numbers are within the limits, then a glaze is more likely to perform well. There are, of course, perfectly good glazes that have numbers outside these limits, but they are a good place to start, and can show you where to make adjustments if the glaze is having problems.