For those wanting to explore an alternate to crystalline glaze without the hassle and headaches: how about Mica Crystals.
A simple variation to the standard crystalline formula fired to cone 6: with a slow cool from 2100 to 1900F @ 200F an hour.
Option: or do a ramp hold at 2025F for two hours.
The formula was set to a median of the top three formula limits, and loosely based on a crystalline glaze recipe:
Frit 3195 50%
Zinc 5%
Mica 20%
Silica 25%
Rutile