Still - all else being equal - it would appear that since you have to make a choice of which set of posts to connect a single wire to then the mid/upper would be the right ones, as Silversmith suggests. At a minimum, there may be no "audible" difference, but to whatever degree there is a binding post effect, it's being minimized.
How to connect bi-wire speakers
I have a pair of Sonus-Fabre Guarneri speakers, they are available for bi-wire, and using a pair Silversmith speaker cables and Audioquest Everest jumper. Should I connect both speaker cables to the bass drivers or positive speaker cable for bass driver and the negative for tweeter? please comment. also is the gold binding post for positive and the silver binding post for negative?