Basically, the TV linkage on the trans should be all the way back at wide open throttle, and all the way forward at closed throttle. It should start moving (via the slot) shortly after you start to open the throttle.
Ok, I understand. I think that is all I need to know to make something myself without initial measurements. The linkage has some available travel "forwards" (i.e. up) while it's disconnected like this, so I assume the spring in the diagram is to pull it fully upwards at closed throttle. Then the rod can push it down/backwards throughout the throttle travel.
I guess then, the length of the rod should be whatever the distance is between the two mounting points when the TV/kickdown linkage is fully forward, correct? Thanks.