That now depends on a few things. First is the design of the shooter. Does the shaft (or other similar pivot point) rotate with the shooter? If not, then is there another rotational point that does?
In the past, my team has used potentiometers similar to
these on DigiKey. If you drill out the center of the pivot point and tap a hole for a set screw, it is very easy to grind a flat spot on the potentiometer and hold it in that way. If you go for the Vex potentiometer, you will have to improvise a bit (I have no experience with those).
Programming one is very easy, too. Just wire it into the Analog Breakout in slot 1 of the cRIO to connect it. If you are programming in LabVIEW, you can open an analog input, and get the voltage from it as it spins. From that voltage, you can determine your upper and lower limits, and determine what angle your shooter is at based on those voltages.