If you open the cluster you will see the light socket/compartment where the bulb sits and points at the "prism" plastic fiber optic ribbon. There is thick aluminum tape designed to fix holes in exhaust lines that you can use to line the inside of the socket/compartment. That will reflect a lot more light into the line and down toward your gauges. White paint will work, but not as good.

__________________
1982 300CD Petrol/Black Leather