While we are at it, I figure the spring that came with it should be installed the same way as on this page? http://www.slagcoin.com/joystick/joystick_components.html
So between the mounting plate and the microswitches ?
Well, it's actually between the joystick base and the actuator since the pivot point on the joystick base is at/below the mounting plate.
The spring will be above the microswitches, since the actuator is what presses the switches.
When you push the handle to one side, the spring compresses slightly on the opposite side.
When you release the handle, the spring de-compresses, pushing the handle back to the upright position.
There may be other spacers or washers in addition to the e-clip.

Disclaimer: I've never worked with the ServoStik.
Scott