I'm going to cover the plane in fiberglass clothe. I understand I need to fill and sand the bare wood before I start covering. My question is what's the best filler to use. I have some SIG sanding sealer which is a butyrate based filler. Is this compatible with Fiberglass? Or should I look at something else, microballoons perhaps?

Another question is, I'd like to use as much water based products as is practicle. Latex (or is it Acrylic?) paint from War Colors being the final surface product I plan on using. Since it's been a long time since I did this is there any new processes on the market that's safer as far as fumes go. The butyrate stuff mentioned above would be better avoided as far as I'm concerned.