On an old set of instructions for V4, the sensor was shown 30 - 40 mm behind the bellcrank pivot. I could not do this in my first plane, a profile with the sensor in the fuse. It ended up several inches behind the CG and pivot. It worked fine, and I discussed it with Rogerio years back. Since, I use similar position a few inches back of the bellcrank pivot for convenience. I have flown a friends who tried a couple of different mounts, including inside the battery compartment at about the leading edge of the wing. A very convenient positsion for any adjustment. I could not detect a difference from mine, nor could he. He also tried the original suggested position and could not tell a difference. But, as they say, your mileage may vary. Ken's word was probably from my mouth :-).
My understanding is that the sensor and timer are acting on nose up angle, acceleration for sensitivity, and force for G-force, not directly on rotation or rate of change of rotation.