It's both not as complected as ya think and even more so
Just about any switch will do, I prefer the momentary switch (push to off, but doesn't stay in that position) but any toggle that fits would work fine too - I'd recommend bringing the throttle housing with you to test fit. The way most toggle switches are shaped ya might have a tough time gettin' one in there and the Rat Shack folks are pretty clueless these days unfortunately. I would also very much recommend soldering those connections so grab a soldering gun while yer at it if ya don't have one.
The only thing with the wire is making sure it's of a similar gauge, if it's the same size or larger (the wires themselves not the plastic housing ofc) the bike will never know it's original intent. I used an old USB cord to extend my electrical system, handy as it's four wires & a ground all nicely bundled together and even shielded - they are
a lil on the skinny side which increases resistance, but no problems so far