It seems there are only two reasons to make your own cable...
1) To save money;
2) To make a custom length -- in a speaker cable that would likely be something shorter than 3 feet.
Now I'll spout my opinions, which you may feel free to ignore

but they are based on thousands of live gigs over many many years.
All you need in a speaker cable is that it be electrically sufficient (that is, the wires are thick enough to carry the amount of current the amp produces), and that it be *reliable.* Oh, and one more thing: *Reliable*
You will not hear subtle differences in tone on stage. You just don't want the blasted thing to short in the middle of a performance!
So, as for 1) above - saving money - with Speakons, buying at low volumes (like two of them) you'll be paying $5-$6 each, so you're out $12 or so. The wire is probably a couple of more bucks. So maybe $15. But there just ain't no way you're gonna build the cable to be more reliable than a factory can build them, said factory that does nothing but make cables all day every day.
You can get a 12-Gauge Pro-Co Speakon cable in a 3-foot length for $25, and it will last the rest of your life. Don't sacrifice reliability just to save ten lousy bucks.
As for 2) above - making an extra-short cable, the difference between a 3-foot cable and a 20-inch one is nil. Don't bother.
Just buy a good cable from a reputable company. I suggest ProCo, which are available online from
Sweetwater or DirectProAudio, since I've been using them for 25 years and have never had one fail.
Good luck with you speaker-connecting endeavors
