Build is on the rooftop edge, as far as you can get. 1 Ogre for agro, because the build can't be pathed to, so they will path to the crystals and if TB is down, they will hit it.
I might try to replace mortars with more wisps and bring in warden builder as well (maybe?)
Party: 1 TB monk (mid rooftop, just make sure both stacks are getting boosted), 2 summoners wioth monk/huntress pets, 1 other (builder?)
Test run 29:53 combat
16,144 mobs
2nd run with all warden (but was 23-35, so about the same) 27:52