Why get OCD about a few degrees of angle? The number of degrees of advance each unit provides is far more important. Check the advance with a delay flash timing light to see if they move the distributor housing the same amount. Vacuum advance is only a consideration at very light throttle cruise conditions, as it goes away entirely as soon as you step into the throttle to accelerate, pass, or even climb a small hill. it's only function is to enhance gas mileage at light throttle, high manifold vacuum conditions.
Jerry
