I've seen DG-800's with grey tinted sheet plastic put in front of the
moving card compass to cut down on the reflection. It seemed to work
well. The tinted acrylic sheet material you can buy from TAP plastics
or similar. Secure with screws into the compass mounting holes. You can
still see the compass fine.

I also believe people have tried shimming the Precison moving card
compasses in their mounts, putting brass washers behind both screws on
one side to deliberately skew the compass sideways to kill the
relection. I am not sure if this even works. It also introduces a
heading error but who is going to use the compass for such precison
anyow - and since we all get our compasses swung frequently this would
of course be included on the deviation card.

I have a Precison moving card compass mounted up on the console in my
DG-303. The relection in the canopy can be significant and it was
annoying me and I had intended to do something about it, but I just got
used to it.

Darryl