On Sun, 13 Oct 2019 20:33:20 -0400, Paul wrote:

The IBM mouse above, the microswitches look "normal" sized to me.

Hi Paul,

Here are more pictures of that IBM mouse, which I'm still using now that I
refurbished it (although I had to glue a side stick on it to keep my
fingers away from the right mouse button since it's a poor design for huge
hands like I happen to have).

Anyway, here are the pictures I took when I disassembled it:
https://i.postimg.cc/YCnQTjyX/mouse01.jpg
https://i.postimg.cc/4yPYtFD8/mouse02.jpg
https://i.postimg.cc/XNsNfFZD/mouse03.jpg
https://i.postimg.cc/mknG0YCL/mouse04.jpg
https://i.postimg.cc/3whH5J4v/mouse05.jpg
https://i.postimg.cc/fTXw6P21/mouse06.jpg

The tilted LED simply lights up the middle mouse button (AFAICR).

If you want, I can snap a photo of the side stick I glued on to make it
less error prone, where I learned that it's critical for a mouse to have a
landing space for your right-mouse finger to "rest" without being too close
ot the right mouse button itself.