I'm curious why Hughes would borther with that... You can't adjust either location (lifter or rocker screw placement). You can minimize the sideways push on the screw by having minimum threads exposed (the longest pushrod you can for your assembly...) but that's it. What I learned is you want the roller on the exhaust flange side of the valve tip at exactly 1/2 lift. The arc the roller traces places it furthest from the shaft centerline at mid lift if the geometry is correct. The sweep looks a little narrow to me but if the cam's moderate that would be why. It placed well, providing the tip starts on the inboard side on the base circle, then moves accross the tip to the exhaust flange side at mid lift, then back to the inboard side at max lift. Needing correction is the result of the valve job being off. I'm hoping the heads were fixed rather than out of the box. I would not run shims if this needs to go higher in the rpm range (above6500) on a regular basis. Shims do not allow for the best support of the shaft.