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. 

"0 AWG"


It might be a good idea to push the bong aside for a few days so you can get back in touch with reality.

Amps: Manley NEO 250 monoblocks
Speakers: Thiel CS2.4

I have correct speaker cables, for me, when I hear more than I've heard before and didn't spend an arm and a leg to do so. Plus, the overall balance and stage are "just right."