I don't know if this really counts as good or even relevant advice, but since no one else has replied yet....
I just did the cabin painting in my 12 this weekend and it seems to have come out as well as I could have hoped given I'm using rattle can paint that is not terribly durable. I basically didn't worry too much about scuffing around the rivets. I've had good luck cleaning with acetone to remove the ink and other surface marks, scuffing with a Scotchbrite pad as well as I can very quickly (which means just a couple of seconds between each rivet pair), then one more wipe with acetone and a final cleaning a commercial auto degreaser. It took 3 hours to prep the cabin and canopy frame this way and apply 2 very light coats each of self-etching primer and paint. The paint has adhered well, no peeling anywhere including on the rivets and even in the 90° heat this week. I should mention I painted the side panels and baggage floor previously.
I will say if I had to do it again, I would have painted all the panels before installing them. Even with minimal prep, those rivets are a headache to paint around.