Consistent Sub-29 combat is possible with better stats and wrath usage.
West to east, all should fit on 4 DU BB: Hermit Shroom - Warden - App

• DST ideally a smidge closer to west side so it gets buffed by summoner pets

During wave:
1x TB: Hint 1 on top of the tower stack aiming at Hint 4 (bounce off the ground). Shift hero around until both djinn lanes become active.
1x warden builder (for more tower damage) after towers are upgraded. Place this split outside of vision/aggro otherwise djinns may get frozen in place and/or spiders may hit the stack when this split walks by. I park it at hint 2 but any safe spot is fine.
2x monk/huntress summoners on Hint 5 (bottom of stairs)

Speed Optimization:
Position TB split in a way that the djinns on the east side flow into the area without bumping into other djinns or the wall at the mouth of the opening to the main map area. This should ensure that the eastern djinns die faster than the western ones, allowing for more consistent TB uptime and faster runs overall.

Troubleshooting:
Clumped east or west djinns: reposition TB monk on top of the towers a smidge towards the side that is stuck. Standing on the warden towers while slightly closer to the app towers than the shroom is what I've found to be ideal 
1-2 stuck west djinn: make sure DST is getting buffed by monk guardian pet. The best way to do this is to build the DST slightly closer to the summoners than the LTs
South crystal destroyed: TB monk weapon possibly knock backing back enemies, follow guide and shoot towards hint 4 (bounce off ground for best results)
North crystals getting damaged: make sure auras are monk guardian pet boosted
Wyverns getting stuck: make sure shroom pit is getting monk guardian pet boosted