EQ heads, Chevy rockers and what studs?

Nice.... looking at the 2nd-to-last pix in the instructions, it appears like the height and orientation of the valve axis to the center of 'shaft' may be pretty good for geometry. (Assuming the pix are accurate and I am seeing them right...) Imagine a line from the center of the shaft to the roller-tip contact on the valve tip; if it is perpendicular to the valve stem's axis at mid lift, that is the best you can do for the height of the shaft.

http://www.hughesengines.com/Upload/productInstructions/HUG1555new.pdf