This isn't an answer per se, but rather an answer as to how you can find out. Try it by experiment.
- Connect together a small battery, micro controller and the compass.
- Assemble on a stout reinforced pcb, laid out symmetrically
- Add a spindle of something like M10 studding or bolt and nuts.
- Mark and record bearing of PCB wrt a proper compass.
- Rotate in drill for brief time. Suggest some form of eye protection.
- Record finish bearing.
- Repeat several times from different starting bearings.
The micro controller is programmed to read the compass and store the readings in persistent storage. After each test you off load the readings for analysis. You should be able to correlate the start and stop positions recorded electronically with the manual ones. You should also be able to see if the intermediate results make sense.
You could further refine the experiment by incorporating an optical encoder disc onto the studding. That would allow more accurate intermediate calibration.
This might all seem like hassle, but might be the only way to satisfy yourself of the device's capability. Call it product R & D. Are you developing a better Sidewinder?