Closed Loop Counter Position mode

I am making a winch using a MDC1460, which I want to be able to tell to go to a certain position and then back again. E.g. Go 1000 revs out and -1000 revs back.

I was thinking of just using one proximity sensor on the wheel to sense a spot on the wheel. Than I would use that to count the revs. Is that something that I could use? It would then just be a digital signal going high every time the wheel turns on rev.

If that method is not possible, I could perhaps then use an encoder to count the number of revs. I figured that I could use the Closed Loop Count Position mode. However, because of certain circumstances I cannot put the encoder on the back of the motor. Can I not just put it at the end of the gearbox, as shown in fig 45 on page 79 in the user manual, and set the motor speed to the gear speed. I have a 3000RPM motor that is on a 20 gear, giving me 150RPMs out at max speed. Can’t I just set the motor max speed to 150 rpms. That way when the gear has reached the max speed according to the encoder the motor is also at its max. Is this a solution I could go by or is there another way?