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, yes there is a lot of ignorance in this area, so let me try to explain how membrane damping works. When amplifier outputs positive voltage membrane goes forward. Motion of the membrane is caused by electric current thru the coil. When membrane moves on its own in the same direction it produces back EMF voltage of the same polarity. This voltage will produce current that flows from the speaker to amplifier. This current has opposite direction now, producing force that moves membrane in opposite direction - in effect stopping it. This current is equal to back EMF voltage divided by impedance in the circuit including cable, amp’s output and speaker itself. Even if we assume only resistive part of speaker’s impedance (bass frequencies) it is still about 2/3 of rated impedance. For an 8 ohm speaker it will be likely around 6 ohms. So now you have 6 ohms in the circuit and likely another 0.1 ohm of the woofer’s xover coil. Reducing down cable’s resistance (0.05 ohm for 2x10ft gauge 14 wire), won’t change anything since you already have 6.1 ohm in the circuit.
So, for the purpose of the membrane damping best effective DF=1.5 (nominal 8 ohm divided by resistive part of the impedance). When we choose an amp with DF=25 it will lower overall damping by about 5% (in comparison to DF=2500). Changing wire gauge from 16 to 4 will improve damping by 1% only. The easiest exercise you can do is to take woofer, short it and try to move membrane by hand. It will be hard to move it, regardless if you short it with short jumper or long cable (you won’t feel any difference).
b4icu said on 2/19/2019: " I’m no more available."
Yet, here you are. Now that is a disgrace.
You`re funny kijanki. Ever thought of trying out those calculations in real life settings? And if you did, do you have the skills to understand what you`re observing?

unfairlane, claiming that only speaker cable or amp's output impedance affects damping, without taking into account resistance of the coil, shows lack of understanding of basic principles.  It also appears that you share this lack of understanding, but at least I made you smile.