What gauge are the throttle wires?

I'm going to make an install of my whole system and the throttle and 3 speed wires are very short so I want to order a 3 core cable from ebay but I don't know how thick they are.
I guess it's somewhere between 22awg to 26awg

They only carry about 5ma which is so small that you wouldn't even bother trying to chose because of electrical characteristics.

Chose for modest physical strength (snag resistance) and/or what you can get - anything will work.

Yeah last time I just snipped the ends off an old USB cable, worked great. Shielded, 4 conductors, and free.

Yeah the physical strength is also my only main concern but it's ebay, the cable is not next to me so I can't feel how thick it is.
Last time I ordered (don't remember the thickness) it was much thicker than the usual which was too much...
Also I don't want it too thin because sometimes the triple crown fork hits the wire (with it's rubber bumper if the cable is not secure) and it can damage a super thin wire very easily

FWIW.

USB cable with JST & heatshrink works very well.

If you want the best cable, look for Mil-Std M27500 grade, 22AWG, but its not cheap.