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. 

As in any other cable. No particular significance of any type, at Audio freq. 
The only characteristics I found significant, is the cable resistance vs the Amp's DF. 
It works all the way up to the calculated value (improves sound) but do not improves above (thicker than calculated).
Google it up. I never thought it matters, after all, we use it, on daily bases, in every electric device on the planet. For some reason, audiophiles tend to think that it is special in their sound system. Well it’s the same. Many of those are life saving equipment, military, space, measurement devices, cellphones and more. None ever tend to go, where audiophiles go: BS land.
Not interested in Googling.
I want to know YOUR theory on how electrons flow through the conductor.
Mr.  eichlerera
Sorry to disappoint you, but I don't have a theory of MY OWN, on electrons flow through the conductor. I learned it as all other from the very basics on conductivity. 
It served me well, on all circuitry I designed, built and tested.