I am in the process of locating a set of Watanabe wheels for my 1970 Fairlady Z. Unless I purchase a new set (expensive!) or get very lucky, I'm going to have to get reasonably close to the optimum offset. I am looking at 15" diameter wheels in either 7" or 6.5" width. I have been using an offset wheel calculator do determine overall effects on inner clearance, etc., and have done a search. What is the maximum amount of inner clearance loss I can go with a stock suspension/brake set-up? Asked a different way, what is the maximum amount of positive offset I can go in both 6.5" and 7" widths without having a problem? My preference would be to NOT use spacers. Thanks in advance.