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

Do NOT use Nakamichi bananas. The advertising on these are false, they are not gold plated copper, they are brass, no copper to be seen. See link below, I cut one open. Use the higher end Furutech or Cardas bananas. Also, it would not surprise me the 4ga. or 0ga. wire you are using are not pure copper, at low prices battery or welding cables might be an alloy.
https://photos.app.goo.gl/yHvsgifGyJVwy5Nh9

" Brass is used in all connectors."
- Not true, check out quality connectors from VH Audio, Cardas, WBT and others. I removed the Nakamichi bananas 2 days after I installed them and replaced them with  Furez TSTSB40NP . 

Don't use Nakamichi termination products, there are much better available. For example:

https://www.amazon.com/Viborg-4XPure-Copper-Conductor-Speaker/dp/B01LC1QI88?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B01LC1QI88

BTW: b4icu, do you really see the need to resort to profanity to get your point across?

This debate regarding brass and pure metals for connectors is probably best written off as just another high end vs mid fi misunderstanding.

I really don't care what banana plugs you will use with your DIY projects. Even thou I can explain why it is the best possible banana plug for your DIY cable.

Please look at this: "This debate regarding brass and pure metals for connectors is probably best written off as just another high end vs mid fi misunderstanding".

Well, all guys (Mr. conradnash, Mr. keppertup, Mr. khiak and also Mr. Willson from BC) who made a DIY cable, with products cost under $60 (what is referred as: mid fi misunderstanding), ended up with a way better sound than with the cables called: another high end…

Are the definitions of Hi end and mid fi, were reversed? Is a high end is what some swindler calls an inferior product Hi end, and a first class sounding product (best possible), is now called mid fi? 

Let's face it, it is not what those cable dealers or manufacturer's call a product, but it is about what that product sounds like, in comparison with all others in its class.

I have the best sounding cable, they call it mid fi, they have a bad sounding cable but it is Hi end, just because they call it like that. What do you charge for that say, as the cable doesn't worth a penny (from sound perspective).