@williewonka I just dug up the cables we found blow everything else out of the water 30 years ago when we had 'golden ears' and really were into audio (and I think Stereoplay magazine (Germany) a few years later tested and ranked them Absolute Spitzenklasse (highest category) next to $500/ft ables). I will certainly try them, but found I only have one long enough (and one really short!). Those are common coax, back then used for cable TV wiring in large multifamily buildings.
I will check your leads/suggestions, see what it says.