Originally Posted by Drip

Even if you're worried that your girls might be too weak, it's probably better to put only 1 girl on the right side tent, because if the second squad takes the path down to the green button, it'll release those moving pests, and you'll run into at least 2 batches of those (if you have a very fast squad with something like 850+ speed) before reaching the final boss. The little HP the boss lost from those cannons doesn't compare to the amount of damage you take from the flying pests.

Quoted for truth; my main squad (full evolved, 70, 6*) was less than half health by the time they got to the last boss and I haven't seen them get that low in a good while.