I would say that you should use the wheels that your manufacturer recommends-
Wilwoods fit under 15's and they were good enough back then and are good enough now to scare me- When I went for a lap with DAve Dralle in Thomas Kirkhams car - I had blisters on my hands from holding on - so I guess 15/s would work out just fine!
ps never had I loved a blister before....
