[RichardJ]

>>Now for the questions: How can anybody advise set initial timing at a particular value, such as 12 to 14 degrees BTDC without knowing<<

Answer: they don't.

from nightrider388's post #13
>>Now, if you use a vacuum advance, (which is pretty much only there for part throttle economy),<<

People that advise using manifold vacuum don't seem to understand that manifold vacuum is highest at idle, 16-20" hg. When you stab the throttle, manifold vacuum drops to 2-3'hg. Manifold Vacuum retards the timing by as much as 15* when you step on the throttle. It stops off-idle pinging and it makes them happy.

Your method of retarding the timing two degrees at a time until it stops pinging is as good as it gets for a stock street engine. Did you do that with the vacuum advance removed/plugged? You should.

>>Would it be advantageous in any way to have a vacuum advance that gives a smaller amount of vacuum advance, such as 15 degrees, and then have a more initial advance, such as 15 degrees,<<

Just simply get rid of the 23* can. Something closer to 15* or 10* or an adjustable can.

The engine is going to ping during WOT, acceleration or when lugging(which you should not do) on a hill or when in the wrong gear. The vacuum advance should only be adding timing during higher vacuum such as when cruising.