So, I've bought an APM2 with integrated GPS and Magnetometer, and I'm planning on putting it on a HoverThings HT-FPV frame.

First up, is anyone using this combo? Have you encountered issues with the magnetometer skewing because of current draw from the motors?

Secondly, is it possible to attach a secondary magnetometer / GPS unit to this board via the external GPS and i2c connectors and have them be used in spite of the fact that there's already a GPS and magnetometer onboard? If so, how does one do so? I assume the i2c addresses need to be changed on one or the other or something.