So with those you gently bend the perch.
Interesting though. I've only seen that on the Chrysler built magnetic pickup race distributors.
Wait. Is that a points distributor?
For street use. I'd still encourage using a long looped secondary spring.
With an ECU, for racing it will help insure no retard at top end.
8.5 on the governer (aka cam plate, aka slots) means there is around 17 degrees in the advance.
That matches well with what you measured.
View attachment 1715766092
Dont think you'll need to reduce the advance any.
I think you're pretty well set up if you pop in a heavy long looped spring and the softer of the primary springs. Then you'll be close enough to fine tune to whatever degree you're interested in persuing it.