I feel your pain and am doing exactly what you mentioned here. 15 inch wheels to clear front disc brake calipers. Wheelsmith will help you out right away. They are 92$ per wheel. I got 5 of them so mine are all the same. You can then get THEIR baby moons so they fit right on the rims without special clips. 6 lug.
I just have this problem with grinding on wheels, then putting modern radials on them. If that works, I am happy for you, but I want them balanced and ready for 75 mph plus. I am very happy with the Smoothie wheels. They are 5.5 inches and are made for modern radials. Hope this helps. I talked to Dave there. He already knew what I needed without asking for measurements. I have them, painted and ready for rubber.
