Performance timing

You need to do some more reading. If you have not done so, read the article in this thread, posted by AbodyJoe

Initial timing settings

Here's what you have, and it all adds up, except that usually, vacuum advance is NOT included in speaking of "total" timing. Total timing is with your foot on the gas, at high RPM, with all the advance "in" except for vacuum, which drops out under a heavy foot---as there is no vacuum

Optimum timing VARIES as there are hundreds of variables on builds........types of pistons, and combustion chambers, cam specs and cam timing, compression ratio, and even the load on the vehicle, which is quite different between say, an A body and a 3/4T 4x4. And of course varies with fuel

Also understand that "normal" specifications, such as the service manuals and other books, spec in "distributor degrees" which is 1//2 the amount of "as measured at the crank

For a beginning figure, start with 15--25 BTDC at the slowest idle you can get, trying to make sure none of the mechanical advance is "in"---which varies by RPM

You want say, 18--20 in the distributor, less with a "hotter" engine. A starting figure for "total timing"---------which is measured at fairly high RPM---to get the advance 'all in' with the vacuum disconnected, is maybe 34--36 degrees.

So "let's say" that you have a dist. with an even 20 "crank degrees" (10 dist) in the mechanical advance. If you set the initial (idle) timing at 15, those two add up to your 35 degrees example.

The vacuum is ON TOP of this figure, and that total of all three---initial + distributor+ vacuum when your foot is light and running "level" at cruise---can be 50--55 degrees, sometimes more.