Recommendation for an audiophile speaker cord that is not "bright"?

Elsdon Wonfor audio LS25.  These are a proprietary alloy  they are utterly transparent with no phase distortions. If you have a well balanced high end system that you like,  these will give you what you have in spades. Pinpoint stereo imaging , WIDE soundstage true speaker response.

The designer was responsible for tellerium Q cable designs but parted company and took forward some of their design principles.  

As the OP, just saying that I loved the sound of my system before I tried the Nordost Frey 2, Valhalla 1 or Valhalla 2 speaker cables.

I have Nordost Valhalla power cords, Nordost QBase and a dedicated main and ground, and a Nordost QPoint under my preamplifier. These were tremendous, incremental upgrades that really "lowered the noise floor." 

So, I love my Wilson speakers and the rest of my system.

I realize I will probably get a lot of heat for saying this but it’s Christmas time so what the hell. The primary reasons cables sound bright can be placed right at the doorsteps of (1) they aren’t broken in yet, (2) they’re in the wrong direction and (3) it’s something else in the system that’s producing bright sound.

I would suggest Kimber Kable Ascent Series 8TC or 12TC cables . I believe the 12TC would work best with your Wilsons. 
(  I understand that their Summit Series Monocle XL is also excellent ) .  

geoffkait- My system is great - it now consists of an Esoteric K1X (bought it in Japan this fall), Shunyata OCXO OP19 master clock, McIntosh preamp, ARC GS150, etc. It sounds great with my run-of-the-mill copper speaker cables. And the Nordost cables I tried were broken in and in the right orientation. I know a bit about the last detail from my experience in the OR.