Quote Originally Posted by VanilleFang View Post
Uh. The best way to do it, as far as I can recall, is having as much DPS on the boss as possible and just let the cannons worry about killing the adds. A tank pulls the adds under the boss so that the cannons can do damage to everything at once.
This is correct, ideally the adds should be so dealt with that the NPCs helpers get to wail on the boss as well. Best I've gotten was a few seconds after the music changes. I'm certain people can push the clear even further back.

I tend to throw in a swing or two if I see one of the big adds at low HP and we're not at the gate.