@holmz - Most of the vintage WE wire being used to construct cables is stranded tinned copper and actually has a pvc dielectric with cotton over that. The wire most commonly used is the vintage KS13385 Hookup Wire, which is still made and can be purchased new. A smaller percentage of the wire I have seen being sold has direct cotton or silk dielectric. You see this (often solid core) wire used for ICs occasionally.
IMO, with vintage WE wire it is about the tone and midrange body. The wire is mostly tinned copper (like Supra cables) and I suspect that and the annealing process have a lot to do with how it sounds. IME, it can be used to make very nice sounding power cables. I have two 7 awg WE wire power cables powering my monoblocks. It also works great for speaker cables.