Lets talk frankly.
Any capacitance on a speaker cable (stand alone, just vs. a measurement equipment), is the fact there are two cables in parallel, for all the length, at a close distance.
Such a capacitance can be fixed easily by building such a cable, from two separates. Capacitance is gone!
Do you thing that now all cables will sound identical?
No!
The factor to build a speaker cables, is custom built, per the Amp's DF and length required. This would effect the cross section (in gauge or sq. mm).
Such a cable can be calculated.
I did.
Not only that, but I conducted a test on multiple participants and found it works 100% of cases.
I also figured, that if a cross section is calculated, adding thickness, will not make any improvement.
So I have the formula.
It was tested.
None of the sound characteristics can be measured by any of the methods of the tests you conducted.
It is about controlling a speaker, that is a coil moving in an electromagnetic field. None of the AP tests apply.