Why you gotta ask such hard questions, Jeff? ;)
OK. Per Post #162 above, I guess your basic Color Decoders are 2170P_4/RYR & RYB (red), GYR & GYB (green). These are global. Blue decoding is set using Color (saturation) and if necessary, Hue. If you need to adjust Color and Hue differently for separate inputs, it looks like that could probably be done with 2170P_4/SCOL & SHUE. These appear to be the sub-color and sub-hue controls. 2170P_4/SPIC appears to be the sub-contrast control.
The grey scale drive controls (purity/neutrality of whites) are:
Grey scale cutoffs (purity/neutrality of blacks) are:
These are all global. As mentioned above though, the different Color Temps (Warm, Neutral, Cool) appear to be configured by add'l offsets to these DRV/CUT controls. What that probably means is that only one Temp can be configured for accurate color balance. So which do you choose? The conventional wisdom is Warm. However, I used Neutral because it appeared to have no offsets, and I think this may have helped in adjusting the DRV/CUT values in tandem (see Post #162 above for more). Don't know if this was the right way though.
If you want to disable the different red, green and blue guns instead of using the color filters, that can be done with 2170P_2/RGBS.
2170P_1/SBRT is a global Brightness (black level) adjustment, if you need more elbow room than the User Menu allows. If you need to adjust Brightness differently for each input, offhand the only way I know how one might do that is via 2170P_3/UBOF. The problem with this control is that it appears to be input & signal & picture mode sensitive (unlike the 2170P_4 sub-controls), so it may take quite a bit of work to configure it for all possible combinations of these. Just so you know, configuring 2170P_3/UBOF for all possible inputs, signals and picture modes means setting up to 56 different values. :) It's quite possible there could be other better ways of separately configuring Brightness via some other black level/enhancement controls in the SM as well, but that's territory I haven't charted. Might be somethin bout this in the XBR910 SM thread though.
Gamma is set with 2170P_4/GAMM. This control is regrettably also input, signal and picture mode sensitive, although in it's default condition, the values are fairly uniform for each picture mode (on my TV anyway). Pro=0, Movie=0, Standard=1 (mostly), Vivid=3 (mostly). Most people use Pro. Lower values will give you a picture with greater sense of depth and dimension. Many people like Gamma set higher on the Sonys though, because it makes the picture more watchable in daylight, and brings out more picture information in darker areas, which tend to get drowned out by phosphor trails, internal reflections, etc. at the lower gamma settings. In short, higher gamma means brighter midtones/easier to watch, but not as much depth or fidelity. See gamma posts above for more.
There are probably some important bits left out, but that's about all that comes to mind at the moment. The XBR910 SM thread may also be worth perusing for ideas. I'd also recommend getting a service manual if you don't have one.
Using only one input can make the calibration alot easier btw. ;)