These mugs have just finished immersion into ice water from 300F (IWCT test). Twice. The LA Matt is crazing but the G2934 is still good. And its surface is more silky and more pleasant to the touch. It is whiter because of a 4% tin oxide addition. This is a glaze surface that would be excellent on most cone 6 porcelains. To adjust the matteness, just add a little glossy to the batch.
G2934 - Matte Glaze Base for Cone 6
A base MgO matte glaze recipe fires to a hard utilitarian surface and has very good working properties. Blend in the glossy if it is too matte.