Well, I'm sure that like any other person, DRKs are fully capable of being bi. But they're born that way, and they're not any less bi if they've chosen to settle down with someone (it's about attraction, not commitment).
Oh wait, bis.
You meant best in slot.
Well now I feel silly.
I'd think it would revolve around minimizing parry on gear, and stacking skill speed/spell speed to reduce your GCD and the cooldown on Dark Arts (if that's even possible). This means you'd probably want to pull from Eso, Gordian, and Void Ark gear, and prioritize Slaying accessories (with *maybe* 1-2 exceptions, presuming you avoid parry).
EDIT: Per Freyyy's response below, Crit is the stat of choice. Make sure you're Acc capped, and then drink in that lovely Crit.