No doubt this will garner some "dood ur doing it wrong"s, but in SP grind @ THM34, since mobs die so quickly I usually equip Invigorate and Siphon TP plus two short cooldown weaponskills (Damnation and Levinbolt) and go nuts with the rest of the group on TP and Battle Regimens.

Seems by far to be the fastest, and much more satisfying than constantly having the mob die when I'm 90% through a nuke cast.