Here are a couple of solutions for wider wheels:

This is Herman Lewis’ black Jalpa with aftermarket wheels. I believe they are 17” and having seen them “live” they fit perfectly in the wheel-wells. I also think he rolled the lips in the front.

I actually like the original look and found a place that could widen aluminum wheels, so my rear wheels are now 10”. There probably is space for 12” wheels, but I couldn’t find 16” tires to fit that size. Picture 2 and 3 here shows my rear wheels.

Laust