JMW 12.5 set up

Has anybody been down the track of using a Feickert Protractor to set up a JMW12.5 arm on a TNT?

I'm trying to find the correct distance for pivot to spindle and pivot to stylus.

I've found various sets of figures for 12" arms, but nothing specific for a JMW12.5.

I have used the supplied JMW jig, but being the adjustable version there's no way of knowing what's the correct setting. And being a second hand purchase I have to assume the arm and probably the jig have been adjusted over the years.

Any help would be appreciated.

Thanks.