I know you are set on cutting, but don't underestimate what a good metal man can do with a roof like that. Before you get to cutting, you may want to play with what you have. If it does not work out, you have lost nothing. Once you get to cutting however....... I have a 49 Ford that had a similar roof. Kids had been jumping up and down on it. It was amazing how well it popped back. Now, except for hundreds of little hammer marks on the inside, you would never know it was damaged. Finished up without a bit of filler.
