I have found that a good paint job requires 90% prep and 10% application. The first step is to remove any and all loose paint and crud. Then clean, clean, clean. I like to try a small test spot in an area that will be covered up after the mods. If you like what you see then go for it! If not you may end up stripping, sanding or wheeling off the years of oxidation. I used self etching primer by rust-oleum and rust-oleum top side paint (rolled on then smoothed with a brush). It turned out nice but not great. I have seen, on this site, the combo you are talking about and the results were very good. The primer is a bonding primer that works very well on aluminum. I plan to use it when I paint my outboard before I spray it. Good luck, you have a good start.