Thanks for that cobalt I have learned it all by simply doing it over the last couple years and reading posts from senior authorities like yourself, cheers!
454 there are no absolutes but there are common factors to consider. As cobalt mentioned this timing discussion is relatively simple in its subject matter but it is hard to describe via postings cause there are so many little differences in eveyones application.
There are 3 main aspects to timing an HEI distributor. Then there are other settings and tweaks that help fine tune it.
Since you are asking about the vacuum advance,,,,you must first dial in the other two main aspects that being initial or base timing and then mechanical advance and the rate that the mech adv comes in vs rpm (the curve). Only then can you really know what you need to do with the vacuum advance.
For starters post what the engine is made up of, is it stock? if not what are the modifications including the cam and compression ratio, stall convertor, gears, vehicle weight/type.
To answer your question if this is a stock HEI then it will usually provide too much vacuum advance but it all depends on where you have set the other two aspects of timing (base + mech)
a couple repeats on my part mark, was typing while you posted