Lots of people say lots of things about how to do proper measurements, some suggest several sweeps and averaging it out, some (like me) prefer the moving-mike technique. However, if you intend to send the measurements to Thierry you should do sweeps, so why not do it like Dirac suggests. One sweep for each speaker on each of the positions below:
I usually do one extra sweep at 1 with both speakers as well, so the total number of sweeps is 19. To do a sweep in REW, use the “Measure” button up to the left in the REW main window.
Point the microphone to the speaker you are measuring, and use the 0 degree calibration file.
You can still follow my guide, just do an average in REW on your measurements for left speakers and your measurements from right speakers, then you will end up with 2 measurements and can continue the guide with the equalizer. Then test and see if it sounds good, and if so you can improve it even further by sending it to HomeAudioFidelity (just tell Thierry you measured according to Dirac single chair).