Once all the parts were in hand the placement of the buttons was measured and marked out in pencil. Once the holes were cut I used a Dremel to put in the 4 indentions that index the buttons and keep them from rotating.
Drilling the mounting holes for the joystick was pretty straight-forward. The slots for the pots were marked out and small holes drilled at each end. A small cut-off wheel on the Dremel connects the dots.
Wiring used quick-disconnects that were both crimped & soldered
After programming, I had the enclosure powder coated for about $40 at a local shop and mounted everything. The final step was to apply a vinyl decal made by friends at Innovative Tint & Graphics
I etched a custom PCB as a breakout for the Teensy that used tall female headers as a socket for the microcontroller. I've been using a standard 24-pin IC socket with the same measurements for the Teensies in more recent projects.