Looks like you've got a good design there, LT.
Maybe add some furring strips on either side of the L-bracket to form a guide channel for easier alignment.
Add two thin nuts sandwiching a star-washer
or a lock-nut to retain the knob on the L-bracket and you're golden.
Use a shelf-pin cover similar to
this or the ones for bookcase shelf pins over the back screw to minimize scratches.
How about a tilt-out wheel design?
CP (green) is hinged at the back so you can lift it and tilt the wheel forward.
Scott
How do you put it back in? It seems that *the force* would keep it in place once you took the wheel out.
Same way you pulled it out --
lift the green and tilt it back.
Gravity does the work keeping the green (CP) down -- add some type of easy-release latch if your gameplay style is vigorous enough to tilt the CP while using the joystick.
Scott