A couple days ago I got a new keyboard tray for my desk, and since then I've done a bit more tinkering to make it more comfortable to use.
When I'd try to use the keyboard/mouse when the tray was fully retracted into the desk, my hands would be running into a crossbar running across the front. I realized looking at it that there were almost all the right holes to mount it in the middle, so I went ahead and moved it over. Only needed to drill one new hole through the right side crossbar
Removing the support from the front right where the two tabletops hooked together did leave them a bit wobbly and misaligned. So to fix that I cut up a new piece of wood, drilled some holes through it, and screwed it in the place where the original bar was to act as a support between the two, keeping them level with each other.
All in all, I'm pretty happy with how the keyboard tray has turned out. At some point I'd like to find some way of getting it mounted at the same height it's currently at without the big wooden blocks on top of the table, but I can have that be a project for a me a few months into the future