Try making your squire tower health based, apprentice tower attack based, monk tower attack based and the huntress hero damage based. Squire for his walls the more health the better, apprentice for his massively strong tower to deal the most damage, monk for the anti air attack an the huntress naturally does a crap ton of damage so she will be able to kill mobs quickly. With my huntress I went with hero damage an ability power she's stupid strong. That's my referred set up hope it helps.