DBM, I feel your pain on those stupid Chevy hinges. I'll be repainting a 93 Chevy truck for a friend this summer and we were swapping out the doors from his 92. I saw those welded on hinges and hammers and words about started flying. Then I saw you just remove the pins and the door comes out, and it wasn't so bad after all. In fact, I think it's actually nicer than having to adjust hinges.
By the way, I'm repainting my dad's horse trailer, the friend's truck, and perhaps another friend's sailboat this summer. And all of those before the Mustang. They will be called PRACTICE for the one that really matters, since I haven't done base or clear in a few years