Response from Poh S Hsu...
I sent my question to Hsu Research by email and got this response the same day from Dr. Hsu himself:
"Yes, I would still recommend placing the subwoofer behind the listener. Best if placed directly behind the sweet spot on the sofa, with the side of the sub parallel to the back of the sofa, 1" or so from the sofa. If that is not spouse acceptable, use it as an end table on wall A side of the sofa. Crossover at 80 Hz. If the receiver allows you to set distances for the speakers, set the distance appropriately for the sub. That should compensate for the distance differences.
"You can run RG-6 cable under the building. We do not believe that cables make a big difference as long as its well shielded."