I'm not sure if this will help but you can go here:
http://www.conradhoffman.com/chsw.htm
and download Conrad Hoffman's excellent arc protractor generator. It will allow you to generate a custom protractor for your arm with that exact P to S distance among other things. Your choice of Lofgren A or B or Stevenson.
Worth a try as it will cost you nothing.
It's all I use anymore. Very effective and incredibly easy to align a cartridge using this arc protractor.
http://www.conradhoffman.com/chsw.htm
and download Conrad Hoffman's excellent arc protractor generator. It will allow you to generate a custom protractor for your arm with that exact P to S distance among other things. Your choice of Lofgren A or B or Stevenson.
Worth a try as it will cost you nothing.
It's all I use anymore. Very effective and incredibly easy to align a cartridge using this arc protractor.