Hi, pro auto repair/painter. Did do a couple 911's years ago that had the 3 stage paint! Not sure what they used to do on a lot of fiberglass rv's and boats! On this boat i have bought, the clear is worn/missing over the years! The mettalic is so large, it feels like course sand paper! I'm thinking urathane automotive clear after prep? Can it be filled in with clear,,,or is there another product, or it can't be done!!!!!!!!!! Thanks so much!!