i used Clearcast +75% (2 Myth Stone & 1 Legend Affix) on a Twister Build with Epiphany (5).
Clearcast gives you a chance to cast your Spell for free, and the Legend Clearcast also gives 100% Cooldown. Clearcast has a 0.5 second Cooldown. i even tried this with no Cooldown on my Build with more Resource cost than i had Resources, and 75% of my casts still cast Twisters for free!
my build wasn’t optimized for using Clearcast, but it sure was fun and did pretty good with what i had.