I've been looking at clay MSDS sheets to get an idea of the proportions of stuff going into the clay. Interestingly I'm seeing the same proportions of stuff between a cone 6 and a cone 10 porcelain which is throwing me for a loop.

I'm guessing that the weight percentages aren't actually correct in the MSDS sheets.

What determines the temp to fire a clay at if the general ingredients are the same?

https://tuckerspotteryeshop.com/wp-content/uploads/msds/clay/MCS - English SDS (2018).pdf

https://tuckerspotteryeshop.com/wp-content/uploads/msds/clay/10-802015.pdf

I've been modifying clays that I like to use with certain additives and I'm hitting a limit where the clay becomes unworkable on the wheel. I think I need to start blending clays from raw ingredients instead of just doctoring clay which is already proportioned in a way that it works well.

I appreciate that I'm a complete newb in this area, but I'm having fun. I'd like to get a better understanding of what gives clay it's properties.