The best people to answer the questions of how it’s supposed to work and what’s the correct way to set things up might be @MajorPainTheCactus and @Azurfel.
We can also go with the setup instructions which have been embedded in the Shader Parameters menu.
There are many parameters which can skew the results if trying to treat the Peak and Paper White Luminance values as absolutes, for example Gamma, Scanline Dynamics, even Colour temperature settings and Phosphor choice.
I’ve always felt the instructions to be a bit vague and inadequate because it says go to RTINGS to find out your Peak Luminance but when you go to RTINGS there’s no one value called Peak Luminance. There are several values each depending on Window Size, which leaves ambiguity and things then end up being subject to the user’s interpretation.
In the past @MajorPainTheCactus has mentioned that certain parameters should be set to neutral/default before attempting to adjust things like Peak and Paper White Luminance.
As for me, I just do what works for me. I just tend to experiment and play around with the knobs until I get things the way I like.
These are some of the “test images” I use:
I think the idea behind Sony Megatron Colour Video Monitor is to harness as much brightness as possible from your display without clipping things or messing up the tonal balance and accuracy.



















