Caleb, I prefer the regular Minwax Fast Dry Oil Base Poly for the seal coats, including the first coat, and do two dips under the crown and one over. The poly will darken your crown and crest a bit. I'm not sure how well the later coats of poly will sit on the lacquer, either. The spar urethane is a softer finish than the regular poly and seems to have target burn issues and may not wear as well. If you are dipping, thin the poly about 3 or 4 to 1 with a good mineral spirits thinner. It is plenty weather and water proof. I've had issues with Testors enamels wanting to run with the polys, so give it plenty of drying time.