I'm not sure this will really help, but LightSpace CMS is one of the main calibration systems in use within the professional film and TV industry, and we (Light Illusion) also provide a lot of direct calibration for many of the major players - be it in training clients to use LightSpace, or as direct calibration for those who prefer to have it done by an external operation.
I can state that the majority (the majority, not all!) of TV based calibration for mastering in our industry uses a Gamma of 2.2, measured by normalising pre-set black/white points.
This means setting black to be 'just' visible, using the Cal Image on the Light Illusion website, and then setting white to be approx 82 cdm2 (23 FtL).
100 or above is not used as most displays distort or clips colour channels at those levels.
The Contrast Cal Image is used to check for clipping.
The room illumination for TV work is set to approx a 'standard' living room environment... what ever that means! But, never a 'dark' room.
(For film grading things are rather different...)
Gamma (and Gamut) is then checked by direct measurement, with 2.2 Gamma as the target, normalising the black and white points the display is capable of.
You can see some of this here: http://www.lightillusion.com/display_calibration.html
including the images used as described above.
Hope this helps.