From what I understand the Home Depot cable that turned green was a batch from way back. I'm not sure it would affect sound. I'm fairly certain that you could use the green stuff to fry yourself with but that's untested. Anyway I seriously doubt that you could tell the difference between 16 and 14 gauge on that distance. I would honestly use the one that I couldn't return.
lsiberian,
Why in the world would you buy a third when you have two and only need one?