There are so many factors that go into wire design, not just conductor material, such as insulator dielectric properties, basic configuration of the conductors, etc., that I would never focus on design aspects, much less one particular design aspect (conductor material).
Cable companies try to distinguish their products and justify prices by touting things like silver conductors, or continuous casting, cryogenic treatment, teflon insulators, static electric charge to polarize the insulator, etc., but, the real value the better makers provide is intellectual--a combination of all factors/material into a good design and critical listening in voicing the product. Yes, it probably does make a difference whether a particular cable is made with silver wire vs. OCC copper, but, that one factor is so small a contributor to the sound as to render choice based on that alone to be meaningless.
I can appreciate that it is pretty hard for some people to actually audition components in their own system so some purchases have to be made as "informed" guesses. For that, you should generally ask around about specific cables (not designs) and find out what people have paired with their tube gear.
I have a local dealer that only sells tube electronics (aside from digital source gear). He likes the sound of NBS cables (but hates dealing with their crazy ownership), Audionote (uk) and Snake River. He said the best cables he has tried in his store is the liquid conductor T.E.O. cables, but he doesn't sell them because of the extreme price of the better stuff.
