How to properly set timing?

The right way is to find out "what it likes" for initial, then use whatever method you can come up with to determine safe max. total mechanical. Drag strip, G-tech, or dyno, what ??

Then curve the distributor to meet those two figures.

"Springs" (rate of advance) is last, to get it to behave in between, so to speak. You don't want too much too soon (mid throttle detonation, etc) nor do you want such a slow curve that you are leaving power, response, engine heat, and mileage "on the table."