Can't i keep the microphone at the good position in my hands ? From what i've seen genelec calibration process is ultra quick, I don't know from Neumann though. If I'm wrong on this do you know a stand that might feat both genelec and neumann microphones, a cheap one if possible ?
For a proper A/B comparison between Genelec and Neuman setup with room EQ you need the microphones to be at the same exact position, and that for each measurement position if you use multiple ones. Without a microphone stand (just buy a cheap one) you cant do that. Genelec is intended to fit on a vertical stand, but I don't such one as I use it for Earthwork measurement mic and the UMIK-1 before that.
A mic stand will also be very helpful in determining a good position for the subwoofers. A quick way is to use GLM for calibration, one for each subwoofer placement and look at the correction graph that GLM produces. A single measurement position was good enough for me, at least, for determining a good enough subwoofer placement. You should find two subwoofer positions, one for each Genelec and Neuman subwoofer, that measures similarly. Otherwise differences in bass response will affect your A/B as they can vary greatly in a room, even at small distances.
Buy some painters tape to mark positions of speakers, subwoofers and measurement positions. The tape can even be written on and wont leave a mark when removed.
Also buy a cheap laser distance meter as this will make it easier to measure height distance, or other distances as well if further away to a wall. It will be much easier to repeat your measurement positions later on.
In my small home office with limited subwoofer placement, the least bad was this. It ain't perfect, but better than the other positions i tried.