If you can find an original vacuum diagram, it would probably be wise to start with what the factory engineers chose. Of course, in 1960 we still had leaded gas with much higher octane ratings, even regular was blended for compression ratios above 9:1. I'd try both ways, ansd see which one gives the best power and/or gas mileage. Back when I could still hear it, I would listen for detonation and tinker with the timing until I could pull a long, steady hill at meduim throttle without getting any spark knock. Now I have to take my grandson along to be my listener!
Jerry
