Just to chime in about DSR (and clarify the background color discussion as well).
Yes, it goes from pure black to an RGB blue value maxed out around 80 or so. No other colors are available for the background. I hate and abhor the blue hued backgrounds, but that's just me. I want max contrast.
The data blocks on the scope are some intensity of pure yellow. No green at all. The subtractive opacity of the data blocks causes them to have some greenish hue to it on some occasions, but when the DBs are turned up to full intensity and compared to a pure yellow draw object on the scope, they are identical colors. The font has something to do with it too... it's thicker in real life than the single pixel type font in VRC. Some scopes in real life are jacked up and look different color-wise than others, but that's just the reality of the equipment in case people are comparing what they see on ARTCC visits.
Everything else from the stored video map is drawn as some shade of gray. It is possible to draw independent objects on the scope in varying intensities of Red/Green/Yellow/White as well, but this functionality isn't present in VRC.
~Nate