[olddog]

No vacuum advance will make your engine do exactly what you describe if you set it at 10 BTDC. It needs the vacuum advance to run properly at anything other than WOT. There will be people who disagree. Racers don't want vacuum because it is one less variable, and they only intend to run the engine flat out. People think it's better cause racers do it. They are wrong!

Bottom line:
Watch the timing as you rev the engine and find out where maximum mechanical is at. Then set the timing to 35 give or take when the mechanical is fully advanced. Then see what you have at idle. My guess is that it will be somewhere approaching 20. That is a typical trick to try to get some reasonable drive-ability on the street without vacuum advance. It is critical that the timing be right at full throttle, because that is when the engine can be destroyed if you get it wrong. The best way to find out what your engine needs is to run it on a dyno.

If you want it to run the best it can on the street, put a vacuum advance distributor in it.