Measuring RPM of a disk: does it matter where the sensor is located?

I am using CCP to measure the RPM of a disk. Currently the magnet to trip the Hall sensor is located on the outside of the disk.

A redesign is going to cause me to have to move the magnet and sensor a bit closer to the axis. Now I realize the RPM of the disk is going to be the same no matter where the sensor and magnet is placed but is there something else that I need to be aware?

Seems to me it might be a bit of an advantage or moving the magnet inboard to reduce torque and balance...

Measuring RPM of a disk: does it matter where the sensor is located?