I used to use a few of the Canon F1-n as well, the laser-matte screens were bitingly crisp especially compared to the bit of blamange they called a screen in the EOS1 line-up.
I do remember there being different versions of some screens, optimised for either wide angles or telephotos - this caused great "hilarity" when lending a camera to someone else or swopping from the 400 to 24 on the same body and forgetting why yhe 24 wouldn't look sharp in the viewfinder!

F3s always looked good when I borrowed them.

Any interchangeable scrren can be bettered by using a replacement Beattie screen - the bees kness!