I didn't attempt to perform those sort of measurements with any level of precision, because I feel I lack the expertise to make any changes to that area.

Knowing that others do have the expertise to change or correct that, though, I'd be greatful to learn how that is done (even if I never try it personally).

I did look reasonably close at pushrod-to-tube clearance, since that was the main driver to the whole exercise, and since all were checked
on the same two lifter bores/same head arrangement. It seemed to me pushrod clearance (or the lack therof) was fairly consistent in each group or type of rocker,
which led me down the path of believing in the possibility the pushrod
side could be the better of the two. The thought was, maybe the valve side of the rocker, maybe even the exact curvature of the pad, might the more inconsistent or
"difficult to get right" area. (?)

These are just gut feelings that developed right after the "Actually, I can't do anything about that" thought crept in, and I decided not to pursue the exact reasons why each one
arrived at a different ratio.