I would say something around the Hooker 9/15 or Solas 13/17 re-pitched to 13/15 would be ok, but might be a little to low. I run a solas 13/17 on my 62T/61X 0.5 Mill over with porting a Riva head at 175 PSI, and Reva Red Pipe and love the way it feels on mine.