I'd want at least a 6" wide rim for that. Especially for handling work.
I don't know about RB cars, but would expect to -at least- need a panhard
rod to keep them out of the fenders on corners.
FYI... Vega GT wheels are 13x6" with the correct bolt pattern. BUT...
they were made for cars with larger wheels studs so you have to make SURE
the lug holes in the wheels are in very good shape to use them with stock
Spridget studs. You -may- also need a thin wheel spacer at one end of the
Ed in NC (with several -extra- Vega wheels in the shed... ;-) )