Clear Day Cables offers speaker cable in a few different models, the only difference between them being the amount of wire in the cable. There is the Standard, then the Shotgun version (which doubles the wire), and the Double Shotgun (which, duh, doubles it again). Jeff advises that the longer the run and/or the lower the impedance of the loudspeaker, the heavier the gauge of the wire.
Different Clear Day owners/users prefer different versions, so you may as well try the biwire cables (if you get them) using just one leg, then both. You can decide for yourself which you prefer with your particular speakers and amp.