I know I'm super late to this thread but I just came across it and immediately had the answer to your question or at least a helpful direction.
If you YOUTUBE Plasmo ( the channel) F/A 18E super hornet at around the 14 min mark he shows how he uses these translucent foils he found online for making realistic optics and LCD screens. These have that halographic look you need for the optics with that reflective but not metallic appearance
These I found by searching halographic nail foil