I use Minwax Helmsman Spar Urethane (satin) on all my wood boats. I paint other products over it as clear wood finishes are not my thing. It's highly fuel proof and other products seem to adhere to it without problems. You can add micro ballons to it to get it to fill better (1st coat). 3 coats are the minimum I would use. Wait 2-3 days between coats and sand with 400 after each coat. If you want it glossy, buy the gloss spar urethane but use the satin for the first coats.