Thanks also to you three for your reactions.
@xpander
So, it's +12 instead of +6dB. I probably done at a very early stage (when starting to use Reaper) the change, as I don't even remember about it. Honestly, I don't want to go again for the tedious recalibration work of all this, which implies also a redesign of the whole mcp.volume and mcp.meters backgrounds. So, too bad, I'm going to let it as it is, at least for a while. Thanks for the info.
@hopi
Hi, mate. I wasn't thinking of making them more darker but making them more long under the knobs themselves. AFAICS in the very few pictures of the original REDD series that I could gather, they are quite high over the surface of the device, so it would make sense, in my view, to make the shadows more visible when compared to the buttons. Think I'm for another Knobman session...