Speaker cable help

It'd be most helpful to know what cables you're using now and what kind of improvements you're looking for. 

The Black Cat Coppertone is excellent,clear and detailed with a touch of sweetness.Kimber is detailed but leans toward cool as opposed to organic.Analysis Plus oval 9 is organic and natural sounding and slightly rounds off transients,a perfect compliment to an overly detailed system.Of course YMMV but these are my impressions.

Wywires should sound excellent with your speakers and amp. This is my guess not knowledge, I heard your speakers but not the Plinius. I just tried Wywires Silver and Platinum interconnects, the former is excellent cable and the latter is great cable.
Alex of Wywires has 30 days return policy, if I remember right.
They are accurate balanced cables, nothing is harsh or too warm or cold. Excellent dynamics and correct harmonic presentation.

By the way, in my system WyWires Platinum mixes with Tchernov and Purist Audio interconnects. Speaker cables are Purist. I first got the Silver and almost immediately upgraded to Platinum, got them both used.

https://www.usaudiomart.com/details/649521886-wywires-speaker-cables/
I bought the Platinum from that man. If you decide to proceed ask him if they are latest or not. If not latest ask Alex about the difference, but you might want them anyway. Take the price down to $550 in any case.