Wiper transmission linkage issue

In my 73 Dart sport the factory wiper bushings had failed but lucky for me I had a complete transmission assembly from a 72 Demon that uses a different style bushing, the issue I'm having is the bushing that links the wiper motor arm to the arms. The bushing from the 2 speed wiper setup is too deep to properly fit the stub on the motor arm and have the clip fit it, I would swap the arm from the 2 speed wiper setup but the "nut" on my 3 speed motor isn't really a nut, it looks more like a splined nut sert, or at least that's the best way I can describe it. I already shaved down the nylon bushing to make it fit but still need to take off more to allow room for the clip, do I keep shaving it or is there a different bushing?

Thanks! -Adam