To do it right, they are going to tell you to strip it, at least to a solid paint substructure. You went sooo far with this project, why not follow your original plan and strip/polish it?
Maybe you can replace some of the worst straight ( not front or rear cap) panels with new aluminum to make it easier and quicker?
Yeah, easy for me to say from 400 miles away...
There is a primer available from auto paint stores, and you can add a flex agent to it so it won't crack in the gaps. I used some of that in the restauration of my 1959
Mercedes a few years ago, and it so far it works well. I drive the car 3-4 times a week, and it has not cracked yet.
They have a sealer/primer at Home Depot, it basically makes a new surface for the new paint, so nothing will crack or give you an unwanted "fauxsomething" finish. It is made by the same guys that make kilz. I think it's called bullzeye or something. You might have to get some metal primer ont eh aluminum first. Most of the modern enamels aren't very aggresive, so you should be fine with the Home Depot stuff if you don't want to go the auto paint routine.