I build Shroom Pits then Lightning Clouds facing the arrows directions
During the first wave I keep out Warden to build the wisps and use F3 for Tower Booster to drop mana during wave while boosting (N) to drop half mana to keep boosting
After first wave is done I take out an Adept Upgrader and keep her out for the remainder of the waves (you could swap her to a summoner with a Huntress Guradian booster when all upgrading is done if you'd like)
Last wave I pull out 2 Summoners (F4) & (F5) and use Huntress gaurdians
TIP: The Lighning Clouds need a line of sight so placing the towers on top of the stairs will be better suited for total destruction