Hi Gord,
I agree that the owner might have to adjust expectations. The solutions are to either get different wheels or pay for tires from a source like Coker.
From my perspective I would definitely be concerned using anything wider than a 205 on a 4" rim. 195 is really the maximum I prefer.
I have a friend running 225/70 -16's on 4 1/2" rims on a '54 3100. They do bulge quite a bit. I agree with the match between your 215/85 on a 4 1/2" rim.
