Don't worry to much about actual timing setting, put it where it idles best, starts ok, and doesn't ping under decent load. Numbers are just starting point. Once set, hook vacuum advance up and readjust carb to set idle speed.
Idle screw (mixture screw) is out for lean, in for rich. 1 to 1 1/2 out is normal.
Vacuum reading should settle down with more timing, 18 to 21 inches of vacuum is pretty good for stock engine.
