On my roadster I have had to replace all the fenders. The right front one I bought at last year's Ballarat swap meet. Apart from the usual rust out where it bolted up to the running board, it was in remarkably good condition. However, it did seem to curve much more than the left one.
To ascertain how much it needed to be adjusted, I traced the curve on a known good fender onto a sheet of cardboard. I cut out the outline and using this as a template, I could see just where there needed to be some adjustment, and how much was needed. It meant shrinking the side bead in places and stretching it in others. The template was invaluable. The two fenders now fit really well.
Hope this trick may help others.
Allan from down under
Wow, what a project. Do you have any pictures to post? I have been FIGHTING a mangled front '26 fender to just bring it back to original. Joe