What is your vision on the car? Thats seems to be the best question in my mind, I have painted them single and base clear, I have found as I get older, I like the more original old school look, and like single stage on my original cars more than anything, on my hot rods and PT stuff I like base clear, I guess it depends on what your doing or intent, I have herd alot of shops do not spray single anymore, I think the young guns just don't know how... as far as durability, I think as long as you buy quality paint on single there is no problem, I had a 66 Hemi Satellite, I painted 22 years ago in single (Forest Green) saw it at a show 3 years ago I started talking to the guy he told me it was the original paint, Looked like it could be, but very nice still held in strong, I had to tell him that was my old car and I painted it 20 years ago, I told him some of the history on the car, and he knew it was mine, this is a pic of a Olds I just sold PPG single and a black 65 Chrysler, the 65 the hood tops of doors were painted 20 some years ago and still looks good the doors sides trunk and roof are all mopar, still boils down to you and your own style...
I had to add that pic love it...