the GS procedure is a good one. when i ask folks to shoot the room, i usually ask for at least 16 but as many as around 30: speaker to mic position. all mics vertical omni, and speakers full range.
overall room response:
1) lower back left to upper front right
2) lower back right to upper front left
3) lower front left to upper back right
4) lower front right to upper back left
critical listening:
the "listening" spot
5) left monitor to ear height middle
6) right monitor to ear height middle
7) both monitor to ear height middle
sussing out width of listening space off-axis
left monitor to ear height mic aligned to left speaker
9) left monitor to ear height mic aligned to right speaker
10) right monitor to ear height mic aligned to left speaker
11) right monitor to ear height mic aligned to right speaker
12) both monitor to ear height mic aligned to left speaker
13) both monitor to ear height mic aligned to right speaker
couch
mic centered on couch ear height
14) left monitor
15) right monitor
16) both monitor
subwoofer (if using one) - placed ~18" off room center line (final placement to be determined)
15) repeat 1-4
16) repeat 5-13
17) repeat 16
this enables "views" of the room from overall, to critical listening (first try), couch, and subwoofer. generally 1 each but a couple per each in the critical listening spot is good as well.
this is done with the untreated room. after the initial shoots, then adjustment by moving speakers and listening positions until the balance is as good as it gets, then adjustments to ensure symmetry at the critical listening position. finally some eq to trim high energy bits slightly (1-2db max). treat first reflections and rear wall. add more as needed to get T60 to <200ms @ critical listening. reflections <= -12db @ >= 20ms. add some (diffractive/diffusive) reflection panels to ensure its not anechoic (you should be able to "sense to room" when its quiet - you have any level of tinnitus "ring" (everyone does at some level) which is apparent, you need more "room")
just saying... you could end up ultimately (outside of the live adjustment process) take a few hundred readings. to put it into perspective, Eric D, told me that for the Galaxy Studios, between the control rooms, master room, and live room, he undertook roughly 15,000 measurements... over the course of 3 years...