7 LTs and 3 DSTs
Wheeling damage all on a jester and also twr boosting is most effective.
Hint 1: Tower move gas traps near crystals
Hint 2: make sure these are inside the auras
Hint 3: Wyvern might 1 hit the crystal so watch out for that wyvern that slips through your auras :3
Hint 4: Use a twr booster monk and stand on the LTs