David I think you are right On the rim widths. I do not know for sure but I think If you used 6 1/2 inch wheel on the front. you do not have to bend the steering arms for clearance. I would be interested in knowing what your backspacing and hub thickness is on your wheels. It would also be interested in knowing what backspacing and hub thickness was on some of the original 6 1/2 and 8 1/2 wheels was.
I would like to hear about your coupe. and where it came from. Poland? You can see my build under the scratch builders forum here at CC. It is burial in that forum somewhere. I went back and found my thread. So here for your viewing pleasure is the link
scratch build
Thanks for posting
Mark