The appropriate scale would have to be 3/8" scale. Why? because the Supercar tires are 16" dia. and 3/8" scale of 16" works out to be 6" exactly. That is the size of the miniature tires I purchased at auction. At this scale the model would be approx. 32" in length, a good size.
To make the rims I purchased a solid aluminum bar stock (lot less expensive than round stock) and cut them down to equal square pieces. Using the original rims as a guide only, I machined the profile as close as possible to 3/8 scale. Not an expert machinist, novice at best. I use a Prazi miniature lathe primarily for small locomotive parts.
Am happy with the final results on my test piece. Original rims are made up of 2 halves riveted together. The scale rims will be 1 solid piece that will look like the original. Next step will be to add the rivets that give it that 2 part rim look, next post or whenever I get back to this project.