Exactly what I was thinking. I think I'll cut the outer sheet metal far enough up to allow access to the inner brace and then mark and cut the inner brace as necessary, bold the new brace in place, trim to fit, and tack in place before I remove the fender from the car to do the outer patch. I'm hoping that way I can make sure everything lines up like it should before I remove all the front sheet metal for some other work I need to do.