The issue of choosing an output data format (e.g., RGB Video Level, YCbCr 4:4:4, YCbCr 4:2:2), and video processing options (e.g., Deep Color or Dithering) is made more difficult by the fact that most charts on video calibration discs are very bad at showing off the subtle differences involved. Step charts usually won't show it, and errors in ramp charts usually don't stand out enough to catch the eye.
For folks trying to work this out for themselves, I recommend Chapter 10 in "Ratatouille" Blu-ray. This chapter is computer generated animation of a fog scene and includes numerous examples of sophisticated color and gray scale ramps. If you deliberately misadjust your video settings, the complicated structure that makes up these ramps will become visible (and quite interesting it is, too!), but the thing to keep in mind is that if things are set up "right", you should not be able to see ANY of this structure in normal viewing.
That is, there should be no hint of false contours or structure that moves as the time advances. It should appear smooth and natural.
One particular time code is especially useful. At 31:04, just as Linguini finishes pulling the jar out of frame, you are left with a static view of the sky seen through the fog. This is a very complicated ramp as it changes in width from wide to narrow as it goes from top to bottom, includes both color and gray scale changes, and covers a significant range of gray scale. You can Pause this frame and study it in detail.
If things are "right" it should look completely smooth, with no hint of the complex structure that makes it up.
Note that to get there, your display also needs to be properly calibrated. Errors in Gamma for example (the shape of the response curve between Black and White, or the equivalent for each of Red, Green, and Blue) will make it hard to eliminate the structure. Of course you can easily make the structure go away by "crushing" the black and white ends of the scale, but to get it to go away with proper black and white level settings is a challenge.
And you may very well find that one specific combo of output format and Deep Color setting in the Oppo works best for this. If you find that to be the case, then replay the whole chapter that way (actually, back up a few seconds into the end of the prior chapter to get the whole scene) and check for other instances of complex ramps.
The circle of light that wraps around the circular window behind Linguini as he gets on his bike.
The foggy sky over the building across the river as he peddles off down the river path.
The fog rising off the river as the conversation develops.
The errors can be subtle. View this in a darkened room and get up close to the screen. You may NOT see any differences, and thus you are free to use whatever combo of output format and Deep Color setting you like. But if you DO see a difference, I think you'll find the best result here to be a good indicator of the best settings for your gear.