perhaps I should rephrase my question more precisely.
That always helps.
If, Im going to do short runs of at most a few feet from the controller, can I get away with 22 gauge wire?
Shouldnt I be able to use pretty much any wire that can handle the ampacity for 5 little bitty LED's?
For 5mm, 20mA LEDs? No problem. Use anything.
I run 1W LEDs (350mA) on 33 gauge wire over a couple of feet. I wanted wire that was almost invisible for some hanging lamps and I had some 33 gauge magnet wire handy so I gave it a try.
I lose about half a volt due to resistance in the wire, that's 0.5V x .350mA = 0.175W power loss. One-sixth of a watt spread over four feet of wire doesn't even make it warm to the touch. All I need to do is make sure the power supply has 0.5V more than the LEDs need to compensate the loss.
PS: According to the Internet, 33 gauge copper wire melts at 29 amps