Lakshmi.Prinnysmash said:
»Well RDM can cap fastcast, over cap actually(84 by my count). And capped fast cast may as well be full time chain spell, spells go off at 15% of the casting bar. Worth it if you're into that kind of thing lol
Edit:
Fast cast 5 on pants, fast cast 3 on neck, and add the 99 staff by spell type(14%).
I count 87 max. 14 staff, 1 grip, 10 head, 3 neck, 2 ear, 2 ear, 12 body, 1 hands, 2 ring, 3 belt (assuming anyway), 5 legs, 2 feet. 87% fast cast including traits, which puts you 7% over cap. You could drop the grip, hands, and 5% more FC in the slots of your choice and still maintain cap.
However, Sekundes makes good points. The game client is sluggish and doesn't effectively handle rapid-fire gearswaps, so you'll have issues with your midcast gear when using such a set on faster spells. The 5% Quick Cast is also problematic for anything where you'd want to prioritize potency over recast reduction.
If you have the inventory space (which is a whole other debate), a tiered approach is probably ideal. Use less fast cast on faster spells, but go all-out on slow spells like Stoneskin.