There is probably more to this story than I remember, but I think it's worth telling.
Like expertise and machine tools for building engines, I possess no experience or tools for doing bodywork or paint. Those of you who can do this have my admiration. The paint that was on the car when I bought it was faded almost to a flat finish, and was cracking and flaking off. It was obviously a low quality, quicky paint job. The GS started out having the quarters and decklid stripped to bare metal, straightened and primed. I then did the doors, removing them in the process. The car had been hit at some point in the past and the front sheetmetal on the car was pieced together from a parts yard from whoever repaired it after the accident. I sold it all to a happy buyer, it was rust-free, but nowhere near the quality I wanted. I found fenders locally that were dragged to MN from California. I also sourced the inner fenders from the west coast. Good right side inners are hard to find, as they rust out under the battery in almost all the Skylarks. The hood was picked up from an individual in Wisconsin. The core support came from a 65 GS parts car I had acquired locally.
After the body and frame were separated, the body sat for about 3 years. It went into the body shop for phase I to block it straight, paint the underside and firewall, paint the dash/a-pillars/package tray area, and jamb everything. I got the shell back after about 2 years, but the work was excellent. It was back on the frame within a few weeks of its arrival home. It took another 4 years or so before I was ready for paint.
Phase II started with dropping off the rolling frame/body sans front sheetmetal. Once the blocking and prime work on that were well along, I dropped off the fenders/hood/core support/inner fenders. The fenders and hood were also given a thorough going over - block, block more, and then some more blocking. It was finished to a point where the car shell was finished in primer/sealer, as were the fenders and hood. At this time the front sheetmetal needed to be test-fit before paint. We ran into a number of issues (minor in hindsite) fitting everything, and it took a month of, for lack of other words, screwing around with it, before we were satisfied with the fit. It probably is as good as you can get a production car without welding and grinding panel edges. The top of the car was painted first. It had a black vinyl top when I bought it. I removed it the first year of ownership. I liked the black top, and have seen a number of 64-65 a-bodies with painted tops. The tag reads TT - Champagne Mist top and bottom. Maybe the vinyl top was installed by the dealer or someone else early on. Then the car was painted with the color/clear coats. The painter had it for another 5-6 weeks color sanding and buffing. Phase II took about 20 months. The car looks great - beyond my expectations. The painter really deserves credit, as he went way above any reasonable amount of hours that he put into this thing to make sure it came out right and that I was going to be pleased.