Guys, guys!!
Sometimes you lose yourselves in a glass of water!! There is a simple solution to a screen display which is too bright without interfering with the bike's electrics.
Go to a paper store, you know the store where you buy writing paper, pens and similar stuff.... something like WH Smith in UK, and look for a sheet of dark tinted transparency paper normally used for ink plotters, cut a small piece of it and lay it on your display with some double sided transparent sticky tape. Sorted!
Use your imagination! Life can be so simple if you did....