It still wouldn't matter. As a sophmore mechanical engineering student, you will probably get into this pretty soon in your dynamics class specifically rotational modeling.

Picture the path the magnet travels in when placed at the edge of the rim vs near the center on a rotor bolt. The inner circle is much smaller, with less circumference. So one rotation of the wheel has the rim magnet traveling more distance than the inner one.Lets say the outer path is 30cm and the inner is 10cm. In physics terms this is displacement or x. Velocity as I'm sure you've covered is dx/dt or displacement relative to time. Say it takes 1 second for the wheel to complete 1 rotation. Rim magnet covers say 30cm in this time and rotor magnet covers say 10cm. So the velocity is higher, but it covers a greater distance, so the angular velocity (in radians/second) of the two is identical.

As said these sensors only register that a magnet passed it and they count the time in between intervals. When you input circumference of the wheel, or displacement per rotation, it has the two parts needed to calculate velocity.

Factory speed sensors work pretty much the same way, but they read off the countershaft...which has a much smaller diameter and rotates much much faster RPM than the wheel, so the pulses occur far more frequently, so there's a much better resolution/smoothness to the data points. As mentioned adding more magnets to the wheel will increase smoothness of the display.