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

I like the idea of direct connection much better with high quality connectors. The resulting sound will be better. The idea of splitting the cable into two equal portions and terminating with a spade and banana for direct connection to the binding post is a good option. It reduces the strain on each connector also. The wire link I gave is for very finely stranded copper (thousands) with is very flexible and easier to work with. It is pure copper, not copper clad aluminum which would not sound as good.

I ordered mine and they came in slightly cheaper than I was expecting, £125. They're being cut and crimped this weekend and will be shipped to me on Monday, I should have them hooked up at the end of the week so I'll report back with images.

May I ask from who and what did you order? Fully assembled? Can you provide a link and how they will be terminated? Thanks.

I ordered them from chameleoncables on ebay:

2 of these: https://www.ebay.co.uk/itm/192412561182
And 1 of these: https://www.ebay.co.uk/itm/192044378960

I spoke with the shop owner and he's going to cut the cable into 4 x 2.5 m lengths and terminate them so I have four black ends and four red ends.

I might need to use a reducer or a termination block to connect the binding posts, but I have lots of room so it might fit directly.

Nice choices.  Let us know.  I saw those same spades and they should works nicely. If to big or bulky to fit, then you can buy spade to banana high quality connectors.