BG Demon carbs are designed to work with at least 20 deg of initial timing . just keep that in mind if you tune by what people tell you to set the timing at you will never figure it out yourself .
just turn the timing up until you get the best vacuum .
that is where i would leave the initial and adjust the advance from there to limit timing .every motor is differant.
Keith black has done tests and found that very little hp was recognized when advancing past 34 total timing .
with pump premium 93 36 38 could be risky . on a iron head motor .