PAD speaker cable differences

The Cable Company lets you try cables in your system for couple of weeks, I think. They do charge something for this. Many here used their service and I didn't hear complaints so far.

"if one is right for your system, then the other isn't". Wrong. Not necessarily. Both can be right, but you may still prefer one to the other.
Some think that Proteus is the most "neutral" Purist cable. Also, as far as I know, this is the first single crystal solid copper design from Purist. And,I think, you should add Dominus to your list.
In addition, since we are talking big money, I suggest you try other brands too; Stealth comes to mind.

Yes, excellent post, but it doesn't mean that I agree with everything Nsgarch said. I myself would definitely not audition any speakers using something like midfi Bryston with Radio Shack cables. I would take older Rowland or Pass amp and DiMarzio cables.
Another approach in this case could be to first choose the amp and then speakers and cables.
I certainly agree with the statement that amp/speaker cables/speakers contribute the most to the sonic signature of the system that cannot be radically changed whatever you put upstream.

Nsgarch, I understand your position, I think it is valid. So maybe Bryston would do but please no Radio Shack cables.
Well, we are talking, is the OP listening?

As much as I like Purist cables (never heard the Canorus), I do suggest you consider other brands too, something that will sound different or maybe even better with your SET.
There are Purist fans here and Stealth fans. Very generally speaking, Purist should sound fuller with incredible midrange and deep soundstage, and Stealth might be a little more "neutral" and leaner. For SS I will take Purist any day but for tubes especially SET I don't know, I would have to sit a listen for a few hours at least.