This is a light in the form of a sheet so you could put the printed instruments over it and the parts that are white will glow. You can cut it to a flat shape as long as the plug pins are intact.
Look up Miller Engineering for the light sheet sets.
If your using individual lenses on each instrument then maybe side lighting the lense will produce a good effect with LED's. Usually just the edge will light up better than the face unless the face has engraved details.
For me depending on how big this panel is I like the look of incandescent grain of weat or grain of rice 1.2V light bulbs. The warm light is better looking than the bright white LED.
What plane is this intrument panel for?