RE: Fiberglassing the airplane questions.
When you glass the bottom of the wing only let the resin get a little past half way on the leading edge. After its dry take a razor blade and trim off the excess glass where it meets the resin. Sand the edge of the resin smooth with sand paper, I use 80 grit. Then when you do the top of the wing overlap the glass a little and do the same process again.
Just overlap your seems by a half inch or so, when dry you just sand it all level.
When applying epoxy over dried epoxy just sand and wipe the first coat with acetone, then apply your second coat. Apply the 4" glass first, let dry then sand the edges to a smooth taper (feathered edge). Then apply the.75 across the whole wing.
I use a laquer based primer, home depot latex color, and nelson hobbies water based polyurethane with there crosslinker added to it.
Aaron D.