So on my Inquisitor, I have Twin Fangs and it's upgrade. I'm currently wearing both the 30% damage bonus ring for Twin Fangs as well as a 5% crit chance ring. I just picked up a purple 20% crit damage bonus ring, and am wondering which ring combo I should wear.
Relevant characters stats (without any rings equipped):
Crit chance: 20% (56% when Flanking due to Sneak Attack)
Crit damage bonus: 90%
So if I'm doing the math right:
Crit Chance + Crit Damage Rings:
Standard Attack: Twin Fangs + Flanking + Stealth = 200% + 200% + 50% = 450% Weapon Damage (WD)
Critical Attack: Twin Fangs + Flanking + Stealth + (Critical Damage + Damage Ring) = 200% + 200% + 50% + (450% * 110%) = 945% WD
Average Damage: Crit Attack * (Crit Chance + Chance Ring) + Standard Attack * (100% - (Crit Chance + Chance Ring) = (945% * 61%) + (450% * 39%) = 774% WD
Crit Chance + Ability Damage Rings:
Standard Attack: (Twin Fangs * Damage Ring) + Flanking + Stealth = 266% + 200% + 50% = 510% WD
Critical Attack: (Twin Fangs * Damage Ring) + Flanking + Stealth + Critical Damage = 266% + 200% + 50% + (510% * 90%) = 969% WD
Average Damage: Crit Attack * (Crit Chance + Chance Ring) + Standard Attack * (100% - (Crit Chance + Chance Ring) = (969% * 61%) + (510% * 39%) = 815% WD
Ability Damage + Crit Damage Rings:
Standard Attack: (Twin Fangs * Damage Ring) + Flanking + Stealth = 266% + 200% + 50% = 510% Weapon Damage (WD)
Critical Attack: (Twin Fangs * Damage Ring) + Flanking + Stealth + (Critical Damage + Damage Ring) = 266% + 200% + 50% + (510% * 110%) = 1071% WD
Average Damage: Crit Attack * Crit Chance + Standard Attack * (100% - Crit Chance) = (1071% * 59%) + (510% * 41%) = 824% WD
So it looks like Ability Damage Ring + Crit Damage Ring is the winner from a theorycrafting perspective, but I just want to make sure I havn't overlooked or miscalculated anything.