So what I'm after is trying to calculate some varying geometries off different bits.
So the order of planning looks to be:
1 - document cam lift
2 - multiply by rocker ratio
3 - take that valve lift to discover mid lift for rocker pivot to tip 90 degree angle (this is why I want the valve stem angle, though I can consider the valve stem as 0 degrees as the absolute reference angle)
4 - take the pivot length (?) to calculate where the pivot goes in relation to the pedestal mounting surface. This would be to build either custom shaft pedestals or rocker shaft bedding.
5 - take the push rod angle to see what the optimal mid lift point is along the curve of the rocker. For scavenged rockers, we're almost assured to be off the optimal by varying amounts. My understanding is that the angle of the push rod from vertical at rest is the same angle up from horizontal along the rocker's rotation.
6 - once the most optimal adjusted pivot point for that rocker is determined, either measure and order push rods, throw those rockers out, or start massaging the number to see if changing the rocker shaft axis or adding lash caps or getting longer valves will help. I recognize sub optimal push rod to rocker geometry hurts actual lift ratio and stresses assemblies.
In the simplest terms, I want to make some garbage on my mill to put rockers on my engine that were made for something else. It might work, or might blow it up. Smarter and more educated people than me have messed in this arena and not really come up with anything, but I'm bored and like spending money.