Vacuum Advance Question

I don't have timing tape, but my dial back light is new and was calibrated last month. I'm using a limiting disc in the dizzy that only allows 14* of mechanical, which is all in at 2200 rpm.
I will see if I can shorten up the travel on the 8.5 canister a bit and give it a shot. Should I adjust the can to respond only to the vacuum spike off idle ? (Light load)