I agree with the comments above regarding the large panel replacement while the body is mounted on a rotisserie. Idealy the rotisserie is meant for short term use and is an awesome tool during a restoration. However, sometimes life will get in the way of those short term plans and as in my case it ended up being almost 6 years before taking it off the rig. I was worried about long term issues even with everything out of the car making it as light as I could. I made a center brace for my car - 68 Road Runner - and every time I finished for the day I would put the car back level and set up the brace. It was just some scrap steel and a scissor jack I found in a junkyard. I would set it up in the middle of the car and run the jack up to the body and give it an extra turn to take some stress off the ends. I wasn't sure if I really needed it but it gave me peace of mind and we had no issues putting the body back together. My car had been mini-tubbed long time ago and when I fixed those areas I just did one side at a time. The rest of the body did not require big panel replacement.
Even with this style center brace I would not attempt quarter panel replacement on a rotiserie.
Good luck with your project.