That is the gray-scale adjustments, RGB gain is the same as RGB High end, and is basically like a contrast control for each color's gray-scale (not to be confused with the Gain controls in the Color Management System - CMS). The RGB Offset is the same as RGB Low. I would prefer if these MFR's would just call it Grayscale High and Grayscale LOW, would be less confusing since the gamut also has a gain setting (which is different).
You also need to calibrate the gamut. However, before doing any of this stuff, I recommend performing the below actions first:
Generally the first thing to do before calibrating is to set the GAMMA Preset to 2.2, setup the manual IRIS if needed (if your image is too bright or too dark overall), and then using the pluge and ramp patterns, get contrast and brightness setup correctly. Also make sure brilliant color is OFF.
Then start the gray-scale calibration, but take the 100 white IRE, 80 IRE, 60 IRE, and 40 IRE measurement first before trying to make corrective adjustments. I would then rely on the 60-80 IRE measurement for the first adjustments to gray-scale, get this flat as possible, then go to the 30-50 IRE and get that as flat as possible, and go back and forth until they are all pretty flat and accurate.
Now go to the gamut calibration and do the 75% patterns from the AVS Rec709 disk. Do the white point readings first though (100 IRE at least and 75 IRE). Next, spend time on getting each color within the proper point on the CIE chart by adjusting the settings inside Color Management (Hue, Gain, Saturation). I adjust HUE first, but the order does not really matter all that much. Then do saturation and gain until it is as accurate as possible. Then after you just calibrated the gamut, go back to the gray-scale patterns on the AVS disk and use the RGB High/Low to re-calibrate them, then after that, come back to the gamut again. You can play ping pong as long as you want depending on how accurate you want to get it.
My dE's were all under 2 when I was done I believe, one might have been near 3, but most at 2 or less.
Thanks for the tips.
One difference I find is that you are asking to set the contrast using the patterns instead of a target ftl reading. I had gone with guide and started with ftl of 22, but I think the image is too bright, so I'll try your way next.
Also In the first run I ended up with gamma around 2 with preset at 2.2. I then started with preset of of 2.4 and ended up around 2.2. I am guessing that it was due to the .8 gain screen I am using?