Re: Gel coat filler
Follow the package directions as far as mixing it goes. if you use plastic spreaders, bondo spreaders, you can pop the hardened material off to clean them up.
As for polish and finish, keep in mind you will probably not be able to perfectly match the original, and now a little faded, color exactly.
Fill the holes to a little above the surrounding surface. Once the filler sets up, start with coarse sand paper on a block to take it down. You also might cover the surrounding area with masking tape to protect it from the course paper. Sand and switch to finer grits until you get to 600 grit paper, you would have the masking tape off now and actually be sanding an area larger than your repair.
Practicing this on scrap wood or if you have some scrap fiberglass would be good so you get a feel for how fast it sands, etc.
you are basically doing auto body type repair work, so thing in terms of those tools and techniques.
