Some shops will let you borrow a length of cable, and I believe even some online vendors will do that for a fee that can be credited against purchase.
Just be open to the possibility that the difference is too small to pick out reliably, and that the wires inside the speakers themselves are likely to be no more expensive than this; https://www.amazon.com/Damme-Professional-Studio-Grade-12AWG/dp/B0034KDGFY/ref=sr_1_1?gclid=Cj0KCQjw...
Just be open to the possibility that the difference is too small to pick out reliably, and that the wires inside the speakers themselves are likely to be no more expensive than this; https://www.amazon.com/Damme-Professional-Studio-Grade-12AWG/dp/B0034KDGFY/ref=sr_1_1?gclid=Cj0KCQjw...