Vandersteen 5A biwire shotgun absolutely required?

Cable Company.

Do it right for heavens sake. Presumably, your amps are in between the 2 speakers so that you have short speaker cables and long interconnect. That is what Vandersteen recommends and that is what works best. Bi-wire must have 4 seperate wires to each speaker, otherwise it is compromised. When you spend that much for a speaker, a couple of feet of cable shouldn't be an issue. I tried all brands of speaker and interconnects, and I like Anti-Cables the best. Those high priced spreads only cost more, but do nothing more..many times less than the Anti-cables. These are solid core, and sound the same in all frequency ranges. Try it... cheap and good...something nearly never found.

No, it is not absolutly required .
Yes , you are right - it is recommended (me+).

"Experimenting always costs me $$ and usually the result isn't worth it "

Not necessary. Get some Radio Shack 10 or 12 gauge spk, wire - cost $10-$15. Try it both ways,...pick one.
Simple.

Vandersteen has been consistent in recommending bi-wiring since before the Model 5 was even introduced. Why would anyone spending what the 5A costs be reluctant to do otherwise?

Does anyone know if the Audioquest Mont Blac single run bi-wire is just split at the speaker end or is it 4 seperate leads tied into the amp end?