Just a comment. I would not want a display panel on my preamp.
A display generally causes some noise to be injected into the signal.
I have zero need of any sort of optical display on my preamps. (or amps)
However I DID add a pencil lead thin strip of white material in the knob groove, on down over the face to allow a quick easy visual of the volume position. I also have one on the selector knob.
Did the same thing to my Audio Research Sp-15 knobs.
And prior to those on my Adcom 750 preamp.
Then, at a glance, from across the room I can see the position.