Personally, I would rather do all that work to some good UV-resistant automotive clear-over-color even if it costs a few hundred bucks. There is a texture shot of paint on that Corvair in the "18 month update" and it looks just as rough as a drive-through single stage shoot.....and white is a very kind color. In the wind damage pictures, it also appears that the Rustoleum doesn't adhere that well.
While it's not thick oil-base in a can, I'm using Rustoleum rattlecan outdoor satin black on the roof of my Mustang(was a rotten vinyl top) until I paint the whole car. I am lucky to get a year out of it before it oxidizes.