SPEAKERS JUMPER CABLES

And well worth it

I think only one person touched on this so far: experimenting with the connection orientation yields different audible results that are pretty straightforward in my experience.
Connect to lower terminals and jump to upper.
Connect to upper terminals and jump to lower.
Connect diagonally; + lower, - upper, then jumper to corresponding post.
As they say, YMMV; I would imagine the crossover topology will affect your sonic outcome. I recently bought a pair of single binding post speakers (Spatial M3 Turbo S), and it’s one less thing to make myself crazy over.

"Does anyone sell directional (arrows) jumper cables? Audioquest? Anyone? I don’t wish to put some piece of junk there."

Yes - Paul Speltz of Anticables makes a jumper which is directional.

In my case only "one" jumper on the (-) have the better performance, in my bi wired speaker cable.