At or above the RPM where your springs are maxed out at if you are showing 35 that is 35 BTDC and is your total (checked w vac adv unhooked/plugged) Zero (TDC of the piston) on the balancer is just a reference point and initial fires 10 deg b 4 that and mech adv makes it fire an additional 25 b 4 (the 10 deg point) for 35 total. It's a linear amt (initial amt to total amt) from start to finish EDIT & vac adv will add to the # (circumference degrees on the dampener)up higher yet past the 35