Bi-wiring theory lies in the suedo-technical explanation that for longer speaker runs, the resistnce is halved, therefore the amp can still deliver the dynamic range expected and the SPL's. It also has its basis in that HF signals don't like mixing with LF signals or that to separate is better. I've never subscribed totally to either explanation as both are seriously flawed.
In practice, a good quality cable (note I didn't say "uber expensive cable") will not need to be used bi-wired. Most people neglect to throw away their binding post links (cheap brass coated bits of metal) and this is where false impressions for biwiring are gained. If those cheap links are replced with the same speaker cable you use in the main runs, you'll probably not notice any difference at all bi wiring and there is no solid proof that bi-wiring helps anyone other than your dealer and cable manufacturers.
Keep speaker cable runs as short as possible, and of equal lengths, and forget bi-wiring.
Bi-amping....now thats a different story