Presently using Duelund tin plated copper, I believe 12awg. I run 300B monoblocks with two REL, I use only single wire plus ground to each amp, excessive bass with two signal wires. This is a litz cable, have VH Audio Airlock, a solid core cable to experiment with as well, this 18AWG copper. I can lightly twist two or three runs of this to create multiple gauges, for instance twisting three runs of 18AWG is equivalent to 13AWG.
Variables here is metallurgy, solid core or litz, AWG, number of signal wires to amp. I'm fine with the Duelund cable at this point so haven't tried the VHAudio, just there waiting if I feel the need. IMO, the silver plated PTEF ofc would be a worthwhile experiment. These cables not that complicated to make so experiment away, make sure you use actual Neutrik brand connectors. Also, twist the cables for some level of shielding.