Well, what they hey I'll chime in too. For me, us, we, we like to start with the shortest valve that can exist in the range of .05, or sometimes less before coil bind for the given lift. Idea being keeping all things as short as possible. Rocker shafts close to their anchors in the head, and less deflection, and weight. Personally I like to start the motion from the back of center of the valve, shooting for the shortest sweep available, even if it's off center. That's just me, so do what works for ya.