Fine tuning

????
I believe you mean how do you tell what timing curve is needed right?

As much initial possible that it will still start with and not kick back, then what ever, by trial and error, total timing runs best with like 34-38*.
After those 2 are figured you can play with advance springs till you get the curve=advance rate dialed in.

Example 24*@ idle/initial and 32* total with an 8* advance all in by 2200rpms