26mm round is the standard size pan that MAC, TKB and Coastal Scents as well as others use for their palettes. The 36mm are usually for blush, as far as i know.
thanks for this vid its really helpful , i used cheaper pigments not mac and they dried out using just the alchohol off to buy some glycerin tomorrow , :o)
If you let the pigments dry in the pan first and THEN press them a few hours later there will be less product on the paper towel or whatever you use =]