Both Monkote and Ultracote have their own peculiarities. Despite what you've read neither is that superior to the other. Both need some practice to figure out. Monokote has more colors available. I didn't see anything available for aluminum in UC.

That said, pay attention to how Faye Stille covers wheel pants. The technique is very similar to what you are asking about.

http://www.modelairplanenews.com/how_to/monokote.asp

John