your saying the top rod with the slotted end is one piece? How did they do that? IIRC, the end piece will screw off, its a 5/16 fine thread, but may not show the threads if its all the way threaded. If that is the case can you extend the slot? The lower bellcrank is not special to this model, that are all the same. It only has to apply all the way on WOT, where it ends up on the backswing is not that important if its close. I think there is a lot of play before the kickdown/throttle pressure function starts to apply/ If it bugs you and you want to change the geometry, alter the hole in the kickdown arm off the trans. The closer the hole to the fulcrum, the shorter the stroke will be with equal travel.
BTW, I do run a full manual valve body, but still have the kickdown if I ever go back.