Which curve in a 123 distributor?

I found a 123 among my parts. It has been used in a 60s Jaguar. It was made in April 2009, and has had little use. The small indicator is set on 5. Forgot to look if it has 6, x?, or 16 curves like todays model.
I want to try it in a 420G.
Any suggestions of what curve to Use?
(9:1 pistons if that matters)

This link might help: 123 Distributor manual

Curve “2” should work well, so suggest you start there.