"And this is where colorimeter-based calibration comes
in. By adjusting the bias/gain, and the RGBs, you can
compensate for any backlight flaws and maintain
correct color gamut. "

No. here is a reason there were no LED LCD TVs in the past. They could not get the color right because the wavelengths they needed were simply not there. So they built those HV supplies and used those CCFLs with their own special phosphor. Well it isn't all that special.

The LCD panel has to separate the colors, and there are only so many efficient ways of doing that. You have to have the colors it needs. The spectral output has to be right and matched to not only the panel, but the circuitry.. The days of the 90 degree color demodulation angle being the last word are over. Red is not really red, green is not really green and blue is not really blue. At least as defined by the old standard. They can do whatever they want now, and DLPs took to using seven colors. Like having a seven gun CRT. Try just demodulating I and Q now. (the original red and blue signals, kinda)

One thing though, if you DO deem it that important, what is your reference ? A piece of paper ? Lit by what ? The way I see it you would need a lightbox such as used for color camera calibration. If you do not have that, how do you know what is white ?