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

OP
You mentioned earlier that Ribbons are an exception. What would you recommend for a Mark Levinson ML3  with a 12 ft run to a ribbon array?
Thank you

Have not found the Spec of DF on the ML, but did on the 23.5: >600.
The ribbon ( Magnepan) is still a hard cookie to drive (4 ohms with 86dB/w/SPL sensetivity).
If that would be a coil loaded speaker, it would be a 2 x 0 AWG for 12 ft.
As it is a ribbon, it migh be less (0 AWG would do).

Actually, silver is 7% more conductive than copper but who’s counting?

Be civil, people.  Personal invective is mean-spirited and counterproductive,
      (A certain amount of generalized invective launched into the aether can be fun.)
     As an audio dilettante and a scientist, I find all the discussions of cables not based on laws of physics or blind comparisons to be , well, entertainment.

     BE NICE NOW!
      

I bet you’re not too thrilled with directionality or cryogenics or burn in. 😛