You need to be looking at both sides of the rocker arm. With the valve open 65% ( small block )of the total valve lift, the rocker to valve stem contact should be in the middle of the valve stem. At the same time, the rocker arm adjuster screw [set to show about 1 thread below the rocker surface - or the pushrod cup as close to the rocker as possible] should be in a straight line with the pushrod.
This what I have learned/heard for a long time.