I polish Semi truck fuel tanks, wheels, battery boxes, toolboxes, ect. I use a cheapo Harbor Frieght buffer, and the Velcro buffing pads, Just a "high Nap" one, (it'll say on the package what its best for). The compound I use is 3M technically made for paint, (scratch repair), but it works well on the aluminum.
I haven't made it that far on my Locost, so I haven't had any experience with thin aluminum, I would assume the sides/fenders will be fine, but I'd be careful about applying too much pressure on large unsupported expanses (hood).
This is the stuff I use: