John, you've apparently changed your question. Regardless, though, if
you're not getting the "easy" answer(s) here, you may have to (gasp!)
research it yourself. I suggest you ask professionals in this field, or
go to websites (i.e., forums) of people who specialize in this.
By the way, my personal experience with painting on aluminum is very
limited, but here it is (for what it's worth). In 1979 I wanted a sign for
the back of my pickup truck. I bought a rectangular sheet of aluminum
about 1/8" thick. I don't remember the alloy. I just degreased it a few
times with 1,1,1 trichloroethane (it was easy to buy back then, but is
apparently carcinogenic) on paper towels. I didn't do any sanding or
other abrasive prep. I took it to a paint shop and told the guy that I
had just used the 1,1,1. He tested the aluminum for cleanliness by using
a piece of masking tape which stuck pretty well, and said "that's good
enough." I don't know what further steps he took to prepare the metal,
but the white paint (background) and black lettering lasted for at least
ten years of driving around and being parked outside (NEVER inside!).
Good luck. I would hire a pro for this if I had the money.