66 Dart rear wheel openings / arches

I am in the process of replacing the rear quarters on my Dart. While I am doing this I want to move the front of the opening up as far as I can since the tires come closer there then in back of the well. This will allow me to run a taller tire if needed. I have already purchased replacement arches for both sides but would like to add about an inch or so in the middle of the top to extend the arch forward while keeping the same body line. I have found a new arch that I could cut the piece out of but was wondering if anyone had a section from a repair that they didnt use or if anyone else has made a piece to go in the middle of the arch to move the front section forward. Ive already posted in the wanted section looking for a piece of the arch but I doubt whether anyone has a piece. Anyone else extend your opening forward to get some additional tire clearance?
Thanks
Rod