You've got me interested, Ben. I have not found the Contax's screen to be overly dim (compared to my poor D-70!) but as someone said, brighter is better.
Biggest problem might be finding a finder screen for him to convert--unless he is making them entirely from scratch.
I'd like to get that #3 finder screen with its grid lines, and also have my creaking old ProBack's crop lines inscribed....never found the microprism screens of much use.