In my experience, multiple factors beyond metallurgy contribute to a specific cable sound. I've heard many lush silver-based cables, and more than a few bright coppers. Cable geometry, shielding, grounding, terminations, and mostly system synergy, contribute equally, if not more than metallurgy. And beyond bright or mellow (or their dysphonic counterparts, edgy or dull) there are characteristics like "air" and "depth" and "soundstage" that for me, contribute just as much to the musicality of a cable as the tonal balance.
There's no substitute for trial and error, and the "error" penalty is minimized using a service such as The Cable Company, which allows you to sample at minor cost.
BTW, I have no relationship to TCC, I just find their service top notch.