Thanks for all the help everyone, think I'm all set to do the wiring now.

still not too sure what I'm going to do about the switch, it can reach all 5 positions without the tip on so its not the slot length or the width of the switch arm. The arm doesn't protrude enough for the tip to sit on all the way and still reach all 5 positions, as the tip ends up making contact with the body.
I don't have any power tools or even a dremel to thin the cavity so I'm might have to try something to make the cap sit higher on the switch arm.