Terry,
Interesting you bringing this up . . I've was on-line yesterday looking to update my steering wheel to something smaller. I too would like to shrink my wheel a few inches but am concerned about handling at lower speeds and parking.
My wheel measures 18" O.D. So I'm looking to put no less then a 15" replacement in.
This should give me a bit more room but allow for the same expectations for handling.
As far as fitting a newer wheel on the old steering shaft. Grant and I’m sure other manufactures have installation kits to adapt to older splines for about $6. So don’t be to worried about fit at first. Just find something you like then look for the adapter kit for the wheel.
Also, if you were to pick one up from a bone yard, someone on here once told me that GM wheels from the ‘60s will work on the old bolts. I’m sure we’ll get confirmation about this from one of the experts here.
Good luck
HC