No one actually knows how to lculate what speaker cable they need


It goes back to cable manufaturars, mostly provide no relevant data! to sales and the users. None will answer this!
Whay do you think that you own now the optimal cable to your setup?
I think I've figured it out. 


b4icu
There is so much pseudo science and 
engineering as to be a prototype for "whacko audiophilia" and many smiles so thanks. But I did want to put in a genuine admiration for Keppertup's hands on experiments based on straightforward parameter changes and rational money. I might look for some of that jewelers wire my own self.
I have yet find better than #12 copper (12 foot lengths) for my system, that I compare to live unamplified acoustic instrument sound that I know well, because I play it. But that is just me.
b4icu,

No, really, you're totally clueless. 

Twisting and braiding wires doesn't create inductance, it reduces it. It's just a fact. Running wires straight and parallel increases inductance and crosstalk between conductors. Go rip apart a USB cable, SAS cable, Ethernet cable, HDMI cable, or practically any cable designed to carry signals at any sort of high speed with precision. The signal pairs are always twisted. Braiding is just a technique to uniformally twist all the conductors. No fancy magic there. 
ALL wires have impedance, inductance, and capacitance. We can know this because it's very measurable stuff.
The inductance of a conductor is directly related to it's thickness and dominates the transmission characteristics of the conductor at high frequencies giving rise to skin effect and in part dictates the impedance of the conductor according to frequency. Wire inductance is so easy to precisely measure we can accurately measure the power flowing through a wire using an inductive pick up. Most electricians have these tools in their toolbox. 
The capacitance is a result of the conductor being insulated, be it by air, plastic, cloth, paper, rubber, or whatever covers it. It's unavoidable if you intend to build practical cables for anything. 
The resistance of a speaker cable is almost irrelevant since we're not dealing in DC currents here. We're dealing with AC signals and impedance is the appropriate measure of resistance. If moving huge amounts of current to our speakers was the only consideration we'd all be wiring our speakers with jumper cables, but obviously we don't. 
You genuinely don't have a clue what you're talking about and it's obvious. This is stuff they teach in high school physics. You've got no business running around claiming you're any sort of expert on cables if you don't even know all wires have impedance, inductance, and capacitance. 
As for input transistors on power amps....
NO, they are absolutely NOT purely resistive loads. Even the best JFET small signal transistors have small capacitances at their gate that vary with frequency. That's why amplifier input impedance typically sinks as the frequency rises. Along with that, they have small inductance values, too. If you're dealing with an amp with a stupidly low input impedance like 10K ohm, you're dealing with an amp with BJT inputs. BJT inputs are current driven devices, not voltage driven devices, so interconnects with more current carrying capacity are in order. If your amp has JFET inputs like mine, with a 100K ohm input impedance, less current carrying capacity is required. In fact, you can use Litz wire for the IC on an amp like that very effectively. However, it's not recommended with high bandwidth amps because it can induce ringing in the amplifier because there isn't enough inductace to damp high frequency reflections up and down the line. 
Ya know, you could just look this stuff up and learn before coming here and saying silly things like you do. Unless you've got some sort of documentation or formula to back up what you're talking about, I'm calling BS and snake oil on you. 
ThePigdog: Think of it as Gabriel Marquez meets Hunter Thompson. Then it becomes art. Found art.
For folks really trying to understand this stuff, you could do a lot worse than googling Waldo Nell The science behing speaker wire. 
He discusses real engineering with real math.