I'd like to offer my experience in polishing the aluminum parts on the 'Dog... I've nearly completed my re-build (started in October '19) and what I did on all of my aluminum stuff was set up a bucket of water, purchased wet sanding paper from 320 grit all the way up to 2500, and purchased some yellow buffing wheels from Northern tool, grey & green rouge, and then started lubricating everything with my elbows. The thing to realize is aluminum (Aluminium for our UK brothers & sisters!) forms a layer of aluminum oxide which is harder than diamond, and more insidiously, forms nearly immediately after being polished off; it's this layer that dulls the shine on aluminum.
When wet sanding, keep dipping your paper & part in water as you go, use back-fourth, side-to-side, and circular motion to prevent forming a "grain" in the surface, and proceed one grit at a time, spending at least several minutes before rinsing and increasing your grit #. It's long, it's tedious, and yes, it'll wear yo' ass-out, but the results are nothing short of spectacular. Where tough to get in with the wet sandpaper and fingers, I used a dremel with sanding & buffing drums. Once the desired surface finish obtained by wet sanding, the next, and penultimate steps are using the buffing wheels with grey rouge, then re-dressing the wheel and applying green (super-bright finish) rouge.
The very last step is to apply Turtle Wax to seal the newly mirror-finished aluminum, and I recommend three applications so that there is a layer of wax finish which will seal out moisture/humidity and preserve the shine. THIS WILL RIVAL CHROME, and the only thing to do from this point is to wipe it regularly with soft cloth to restore the luster. There is no product available anywhere that you can squeeze out of a tube which will even come close to this method, Jersey James & Proflyer would probably agree with me on this. I will be posting pix of my resurrected '03 'Dog soon, and if anyone is interested, I would be willing to post a pic-by-pic illustration of my method.