I'm just going to mention this. Ignore it if it contradicts what you know.
20Hz to 20kHz is effectively DC as far as wires are concerned so your speaker cables at these frequencies are simply resistors. The inductance and capacitance is infinitesimally small for audio purposes.
I've worked with copper plates in the GHz range and yes frequencies at the 10^9 are very much effected by wiring and copper sheet width, etc..
At 20kHz or 20x10^3 or 6 orders of magnitude longer the skin effects are barely 3% with a SOLID 12ga wire. If you are using lots of fine strand wire this pretty well disappears.
By the time you get down to where most of us can hear ( probably 15-16kHz ) it is even lower.
A just noticeable difference in sound volume is about 0.5 dB at 80 dB which is 12%
So for the sake of argument in a worst case scenario you can theoretically state that there is a less than 3% drop at 20kHz due to skin effect with a SOLID wire, it would still take 12% to actually hear a difference.
Longer runs of smaller gauge wire just waste power overcoming resistance in the wire. It is not efficient, but it does not model the sound.
Most high end interlink and speaker wire companies are selling snake oil. Like spikes for an amplifier, there is no impact on the sound except what we subjectively believe there is and it has been proven that people think anything that looks impressive sounds better than something that does not look as impressive even if that thing has the exact same guts inside it.
