I'm not a fiberglass guru either, but my understanding is that if you decide to go with bondo, you can put the release agent (wax) straight onto it.
I'm not sure bondo is the best thing to use though. It's definitely working, but if I was to do it again, I probably would have gotten the drywall filler as smooth as possible and then sprayed on polyurethane.
I'm not sure bondo is the best thing to use though. It's definitely working, but if I was to do it again, I probably would have gotten the drywall filler as smooth as possible and then sprayed on polyurethane.