1. Center your wheels/steering wheel so the car would be going straight, if it was moving. 2. Now pull your steering wheel and position the C-shaped cancelling cam open end to be facing 9 o'clock.
Also check if your cam has worn grooves from nearly 60 years of use. If this is the case, reposition it to a spot that has no wear. It can also be flipped if needed. I think if the cam is worn down, it does pull the shift pawl far enough all the time.
My turn signals always acted a bit weird until I did this above today. Now they work great. I previously had the open end facing at 3 o'clock; which would seem now ,in my opinion, to be the wrong way.