Hint 1: 5 DU beams. Build 2 archers 1 mage 1 spider on first wave, then replace archers with ogres on second wave.
Hint 2: 6 DU beams. 2 ogres, 2 mages, 1 spider.
Hint 3: 1 Fireball Tower facing spawn point, stacked with 2 LTs. Your reflection beams must protect them well, otherwise djins will destroy them during boss.
Demonstration Video To Be Uploaded Later