I have a lot of experience biwiring Vandersteens. Use 2 completely separate runs of the same exact cable. If you use 2 different cables, you will hear the difference. One option you may want to consider is having the 2 runs of cable terminated together at the amp end. AQ does it for me, I'm pretty sure kimber will do it as well.
Help with bi-wiring
I have a pair of old Vandersteen 2ci with 8' Kimber 8tc straight runs with open spade lugs. I see where Vandersteen recommends bi-wire so I decided to go that route. My question, however, is how to go about it by: 1. buying another 8' pair with open spade lugs, or 2. sending my current pair off somewhere for a technician to split them into four 4' cables with spade lugs, or 3. Attempting to do this myself. I can do simple electronic work but I feel my cutting this cable in half would open a can of worms that I wouldn't be prepared to deal with. Anyone with experience here, or any suggestions? Any help greatly appreciated! (If you recommend sending them off, could you give info?) Thanks!