to be honest , as long as your archers can 2 shot them , and your tank doesn't die by being focused , i don't think that it would matter were you place your troops.... But yes , the first few timees i did this map i panicked since i was stupid enough to think that i should get out mages to deal with the aoe. SO everyone can make mistakes. In this case its a costly one (8 stamina) , so its good that this guide exists for newer players