SB Rocker Arm Geometry

from "Dvorak's papers"..
improper geometry will look like the rocker tip is scrubbing toward the exhaust manifold side of the valve tip for the entire lift cycle OR PULLING back on the tip of the valve toward the shaft side during the entire cycle.

IT IS IMPERATIVE THAT THE TIP OF THE ROCKER CHANGES DIRECTIONS AS IT "SCRUBS" ACROSS THE VALVE TIP.

A roller tip rocker is okay if the roller center is on the center of the valve tip at half lift in most cases. Raise (with shims) or lower (by machining the pedestals or the shaft stands until you can accomplish that position. But if you observe the movement across the valve tip it should do the same as described for the stationary tip rocker. And that is start contact to the shaft side of the valve while the valve is closed, move across the tip just to center or slightly past, and then return to the original position during full lift. Then back to center at one half closed and back again to the original position when the valve is closed.
,,,see his website for more indepth stuff..