Sorry for the delayed response.
If you want back illuminated switch panels, you need to bead blast the clear acrylic to get it to look frosted and then paint a layer of white on it top and bottom except for the lamp pockets so the light from the lamps goes into the inside of the acrylic. The reason you want top and bottom painted white is so that the light bounces around inside the acrylic and evenly illuminates the white layer where you are going to have lettering.
You then paint a couple of layers of clear and then a layer of black that you will Laser Engrave so that you have a Black panel with White Lettering. This White Lettering will be illuminated with the Lamps that you put in the pockets.
The Incandescent Lamps get hot and you have to have the Brass .005" Heat Sinks in the bottom of the Lamp pockets (when viewed from the bottom) to prevent the lamp heat from damaging the plastic. This is exactly what the Aerospace industry uses to prevent that. However, in their case, the heat sink is part of a filter that shifts the reddish incandescent light to either pure white or the NVIS Green tint.
Now the trick to the white paint layer (if you are trying to get the same professional results like the Aerospace industry) is that that layer must be even and not so thick to reduce the illumination light level or shift its color. None of the Aerospace manufacturers will tell us what and/or how that white layer is applied to reach those professional results. It is a highly guarded trade secret. You also don’t want the laser to etch through the white layer which is why the two coats of clear between the white and the black layer helps you to avoid that.