I just want to use solderless connections for the microswitches on a couple of new buttons I've added to my CP.
I have one of these tools pictured below which I think is suitable for crimping these spade connections (correct me if that's the wrong name) but which bit of it do I use? They all just seem to crush it.
The existing crimped connections also have nice big chunky opaque plastic covers over them. Can anyone tell me what they're called and where I can buy them?

The tool will work fine for crimping, but it's awful for stripping. If it's just a few buttons it'll do but it really is worth it to get something else to strip wires.
The connectors that go from button to button for the ground loop and from the NO tab on the microswitch to your encoder are called crimp-on Female quick disconnects, the ones with the shroud are usually called fully insulated.
Basically all you do is strip the end of the wire(s) you want to have the connector attached to, twist the ends (if the wire is stranded), place in the tubelike channel on the connector, put into the crimping section of your tool and put some nice force down, you basically crush the shrowd and it clamps down onto the wires, resulting in a nice firm attachment. The last thing you want your wires to do is unattach.
Good luck.