man, you guys are doing it the old-fashioned elbow-grease way... I quit doing that 2 years ago!

Go get some 100% pure polyester DRESS liner fabric from your local fabric supply store.

Fiberglass your part using whatever glass cloth, epoxy resin and your preferred method of application.

once your done (only squeegee off the excess Puddles of resin, not the entire surface. A little extra resin can be left on the surface)
Lay down the polyester dress liner on the part and smooth it down using a squeegee (if your cloth has a crease in it, throw it in the dryer for a minute or 2). then LEAVE it on till the epoxy has cured.

The next day, pull off the dress liner and throw it away. Your left with a surface ready for paint, no sanding required!

Also, if you have an area of fiberglass that peels away from the surface, take a plastic baggy, put your finger in it, put a drop of thin CA on the lifted fiberglass, then rub the CA into the fiberglass with your plastic wrapped finger (keep it moving, you'll feel it warm up, at that point you can stop).