I'll get the ball rolling with my olde favourite
argument talking point, Golgoroth.
NOTE: Not sure if viable for challenge mode, but I don't see any reason why it's not tbh
You run the one orb strat as normal until you get to the point where you need to drop the orb. Have the team damage the orb as normal until it's nearly ready to drop.
At this point you have a Titan jump down into golgoroths pit and drop a weapons of light bubble in the entrance to little room where the enemy's spawn in on the left.
Everyone then jumps into the Titans bubble. Golgoroth will then be looking down and firing at the Titan bubble
The gaze holder stands on the boxes on the left drops the orb and then takes Golgoroths gaze. because Golgoroth is looking down its very easy to hit his crit spot from the front.
Everyone can then steps forward into the pool getting maximum time and an already active weapons of light buff.
No time wasted jumping down after the gaze is taken, and no time wasted dropping the bubble or stepping back into the weapons of light bubble.
We got two hunter tethers in as well on the first Damage phase because we had so much time. The first phase saw us take his energy down to under a third straight away.