Separating BiWire Cables

You'll get full range sound. Insulate the unused pair to avoid a short.

Are these terminated in spades?
If they are, can you not connect two spade connectors to each binding post?

If not it shouldn't bee too difficult or costly to re-terminate one positive and one negative connector per cable.

You can certainly do what you propose, but if at all possible it would be much more preferable to have the entire cable connected to the speaker end.

This is Audiogon, why not sell them and buy cables that are more appropriate for your new speakers?

According to Richard Vandersteen, Bi-Wiring is most effective when you use separate cables for the upper and lower connections.