Any hints on how to clean the hull?
Go with one system. IF you use sandpaper, use wet and dry--wet!. You can start with 400 if very badly oxidized, work up to 1400 or 2000. Then go to compounds. Pick one system: 3M, Chemical Guys, McKee 37, Nautical one, Smooth, Presta, McQuires, Shurhold, Starbrite, and my favorite: Collinite Fleetwax for the final.
Buy a good electronic controlled speed buffer/polisher, with good quality wood and foam pads. Yes, you can use a Harbor freight "Chicago", but it will not hold the speed as you press down to do the cutting with the compounds. I prefer the Makita 9237c, but Hitachi, DeWalt, Milwaukee, etc also have premium buffer. (not random orbital).
A good detail may cost you over $1000, so the investment in good buffer pads, and detailing products pay over the long run.