IMO you'll be better off measuring what the distributor is doing. Then go from there.
In general the FBO plate is more difficult to get a good curve shape with. It's fine if all that's needed is a straight line of advance but in general a shaped (aka two stage) advance will produce better overall results.
I know what the distributor is doing the mechanical advance is starting somewhere around 1100 and im getting a total of 26 degrees advance from the mechanical