Black and blue in my opinion looks wrong, but that's just me. I would agree with what everyone else is telling you. Stay with original colors. Especially given the effort you're going through as you'll never be able to cover all the original paint unless you strip the shell down completely.
As far as how to? However the painter wants to as he's the expert and having him do something differently to what he does usually won't 'improve' things.
Technology has moved on since the 60's and there are new paint systems available. I suspect that metal etch primer was used before followed by primer and paint. These days , most people would use an epoxy primer to seal the metal before applying primer and paint. Removing and dissembling the doors , trunk and hood and painting them all separately will give you the finish you're looking for.
Single stage can be used for solid colors, but base/clear for metallic. Again, whatever the painter is used to using is what you should go with.
Last edited by alabbasi; 10-17-2019 at 01:42 PM.