Spar and water base polys are both a softer finish, thus the target burn. Use a quality gloss oil base polyurethane and keep the coats thin. If dipping, thin it 3 or 4 to 1 with a good paint thinner, or just wipe/brush it on. 3 or 4 thin coats is plenty. Minwax Fast dry Polyurethane is one of the better ones and easy to find.