My boat hadn't been compounded or waxed for an undetermined amount of time. I bought it in summer 2018. The gelcoat was heavily oxidized and chalky. I should have given it an acid bath, whatever that is. I used 3M Compound and wax which left it splotchy. I grabbed my bottle of Meguiars Ultimate Compound (auto use) and it did a better and more consistent job of removing the oxidation and providing shiny surface. It's still not the end all for the shape mine was in, which may be similar to yours. If you search UT you see many touting Meg's All in One. If you search forums you see 3M Step 1 Heavy Compound mentioned by those who have tried others and were not thrilled. It's a bit expensive @ $41/qt. After it you're supposed to use their Step 3 light compound with wax, also about the same price. Personally I want to do a light compound without wax and then do a Turtle Wax Ceramic spray coating on top. I watch Project Farm and it outdid sealants in standing up to the elements. On the vehicles I've used Rejex and it's great at preventing leaf stains and enduring being outside. On the vette, I set the bottle on the trunk lid as I wiped it on the rear fascia and the bottle started vibrating, walking its way to the edge. Darnest thing I ever saw. Later I took it in for service and the service mgr wanted to know what I used as he'd never felt anything so slick. The TW wipe one/wipe off would be a lot easier on a large surface like a hull. Rejex can be difficult to remove and no matter how well you think you got it all off, look from every angle, you'll see some still stuck. It has to be applied in very small amounts unlike wax.