using a jumper cable - connect which set of post?

My experience with cars and motorcycles is that they ABSOLUTELY perform better when clean. Maybe the dirt causes tiny amounts of wind resistance...in any case it's an indisputable "personal" fact. Science says that, indeed, "strapped" speaker posts represent a single electrical point to the crossover input and nobody should be able to tell what post the cable is plugged into...the fact that some claim they can hear a difference is something I can accept completely as I now go out to ride my spotless motorcycle.

One more thing to consider--instead of bi-wiring, consider getting a set of really good jumpers between the posts, preferably the same cable you are running from the amp to the speaker. The brass jummpers that come with most speakers are really not very good, and a good jumper can deliver substantial improvement in the sound. I don't have vast experience in this area, but, a friend who does audio for a living generally prefers a good set of jumpers to bi-wiring.

I have always preferred using the Type 4, or CV-4, as internal biwire, with each of the four internal wires going to one of the biwire binding posts.

I wonder why more people don't like high-end audio?

I wonder why you even care.