I did some experimenting last night to see how well someone with experience -- someone who knows what a properly calibrated grayscale shold look like -- could adjust the a TV's grayscale to meet the specifications without instruments.
Here are the results for my 64D7000. The attachments show 1) the grayscale as it came from the factory, 2) after adjusting the white balance (and 10 point controls) by just looking at a grayscale step pattern, and 3) after a grayscale calibration with my i1 Pro.
From the charts: The factory settings with the warm2 color temperature are too red. As expected, without any meter the results of my tinkering are too blue. (I didn't measure the factory warm1 grayscale. I should have but it was getting late. Maybe next time I will.)
Conclusion: "Calibrating" without instruments is nearly impossible. The eye plays tricks with the mind.
EDIT: I forgot to mention that all this was done in the movie picture mode.
Just thought some of you might find this interesting.