Build Forge towards the back of your maze instead of at the front? By the time you get the Forge, your main should be doing so much damage anyway (just through levels, potions and items), the Forge's damage should be irrelevant.
i agree with jhoijhoi. by then, things should be more or less manageable. try adding helm to your main tower ;)
The problem I was talking about was when your main tower's range is already too long. I've run into cases where my main is stealing mass wave kills from my Knusperhexe even when I get the witch a helm and give my main an ax. I would be nice to be able to temporarily halt a tower (other than Mr Iron, how can just use construct).
I think only Rahler got my point lol, I was doing what you're suggesting when I was level one, so please.. I came to a conclusion that an item that would stop a tower it's definitely needed even for earlier waves when, let's say, you want to strengthen your main tower but you want assurance by placing couple more tower. Don't know if you're still following me now if you got the point by now, hope you did lol.