well, i'm in the middle of mine right now too. I used bondo fiberglass. I tried covering up the hole area, looks sort of like an arrow head. Anyways, it wouldnt stay in place. So i cleaned it off, and put some duck tape on the back. Anyways, put fiberglass on it.

Just got done sanding it back down. There's airpockets in the fiberglass. Not alot, but a couple. So after i sanded it down, i put some Bonda Body Fill on it. I'm waiting for it to dry now. Hopefully, it works.