Wow. Sorry I didn't see this sooner.

All speaker wire is is a high strand wire. Where normal XX gauge wire would have XX strands, speaker wire has a lot more. Its to reduce all the bad little properties of electricity no one every puts a 2nd thought to. It also makes the wire more flexible. Other than that it is exactly the same as "normal" wire.

Do this... add up the wattage of your flex watt. Now divide by 120, that gives you your amps. Unless your running a huge rack.... your drawing a whole amp or two right? Flexwatt doesn't draw crap and your small wire will be fine. 18 gauge is good for like 13 amps or something (ill have to check that after work, I gotta head there right now)

and btw I have never seen speaker wire that wasn't copper... aluminum would break too easily being that flexible so it wouldn't make sense. Also to who ever said copper wasn't the best conductor... unless you wanna talk gold and silver....yea it is. General wiring comes in copper and aluminum. thats about it.