Timing advance guru input needed

If you want to compare with a distributor-
The boxes outlined in white are timing from a distributor's initial and mechanical advance.
The boxes outlined in green are approximately the timing with vacuum advance added in.
In between is in between.

upload_2019-8-15_19-18-56.png

Comparing with a factory iron head is all I've got. But assuming your engine's combustion efficiency is similar or better, might want a little less advance from 1800 to 3600 rpm.
Again using a stockish engine as a some guidance, probably want around 50* when MAP is 40 to 50 kPa

All those things 67Dart273 posted play into it so this is just to give you some ballpark.