I would say 1/16th -.100" clearance would be plenty! Judging by your pictures I'd say it's do-able. When I made my brackets for my Viper calipers I had to move things around slightly to make it all fit with my rims. I wouldn't be afraid to clear/machine the calipers slightly on the ends to make it work.
Don't give up your almost there!

Last edited by brads70; 11/28/13 09:20 AM.