I believe Focal, who manufacture some very fine speakers, has the understanding that it does not make a difference. From the Focal site:
"BI-WIRING STEREO LOUDSPEAKERS
Bi-wiring has now been phased out on all Focal speakers. Rather than investing in a function that has become unnecessary (our OPC filters have been designed to do away with bi-wiring), we opted to use our new top of the range cast-moulded, insulated, ribbed terminals to ensure a tight clamping torque."
In fact I use Focal in my entertainment room [Video enjoyment] and the speaker only have on set of wire connections. Just get a decent set of wires