Max position at wide open throttle works well with factory linkage and carb levers, because then it's also in a good position at idle and low throttle, automatically, due to the linkage being solid. Your aftermarket cable setup complicated things.
The good news is you got it sorted out and you can now enjoy it. You did a good job on this one, and ended up with an informative thread in the process. Congratulations on your first transmission build.
