Sorry, I missed that you measured to the sidewall. I do not have the exact same set up that you have, but you have done some great cypherin already! Like I said in my first response, IMHO, I would increase the sidewall clearance to 1 inch. That translates into a 5 inch backspace. I have a Demon with the same rear (B-body) but my springs are moved in using the offset hangers. My cyphern, for my set up results in a 6 inch back spacing...approximately.
