Can't see the vacuum changing by ignition timing, unless the timing increased the rpm with the throttle plates still closed, but you would lower the rpm again with the idle screw.Valve timing yes.If you're getting your total all in by 2200 rpm and your initial is 12-14 you most likely have to put stronger springs in the mechanical advance. You should have your mechanical max out around 3000 rpm. Your old springs may be worn out or just too light.
Rohrt, is that an SD Performance Stump Puller? If so it's the same camshaft I have. I get 12-13 in. vacuum max . Some do have starting problems with a high initial timing,. That can be cured by modifying the advance rate to get the max at the rpm desired with a lower initial, then increase the vacuum advance to get the higher timing at idle. Some have used a hold off switch to allow the crank to start rotating before the ignition is powered, a relay can be used as well I don't have a problem with 10.5:1 but 12:1?