Specifically, I am asking about Carapacho Cuffs (-15% stoneskin) and Seigal Sash (-8% enhancing). Do these cast time reductions stack by addition or by multiplication with fast cast?
.52 fast cast + .15 gloves + .08 belt = .75 = .25 cast time for stoneskin
.48 cast time from fast cast * .85 from gloves * .92 from belt = .375 cast time for stoneskin
Based on eyeballing my stoneskin, the spell appears to consistently go off somewhere between 20-25% on the cast bar. It doesn't see too accurate, so I was wondering if anyone knew for sure.