My limited experience
2 years ago I polished both the hull and deck/cabin top. I used the Meguires system. I used the rubbing compound, then the fiberglass nourisher (sp?), and then the sealer/wax. I liked the compound and nourisher products, and the wax looks good, but 2 weeks after I had finished, I came back to my boat to find rain streaks that I could not easily remove. Next time around I am going to try an acrylic sealer that I bought at the annapolis boat show(I forget the exact name), and if I am not happy with that, I will try my car polish, a product called Zaino that I have had good results with. I know a lot of folks here use the island girl products, and that might be the trick for you.