Agree. I would not overthink the speaker cable thing. Far too much nonsense is written about this stuff. You just want something that does not affect the amplifier Zout, so the individual wires should be reasonably thick, and ideally not too capacitive or inductive. With the co-ax, you have to remember its LC is lumped, so you have an L element there are well - the amplifier is not just seeing the capacitive part of 250pF/metre as in Sevy's cable. In any event, any decently engineered amplifier should easily be able to drive a few hundred nano-Farads directly without breaking into any sort of sweat - make sure you have plenty of phase margin, use an output LR coupling network
(0.5-1.5uH//2.2Ohms) and a Zobel from the amplifier output rail to 0V (8.2 Ohms in series with 0.1uF), ideally on the amp module PCB to keep the loop area small.
I made all my cables - I use good quality gold plated banana plugs or spade connectors, thick cable like the one below from Amazon and then I feed a nylon sheath over the whole thing with heat-shrink and silicone sealer to secure everything at the ends. The thick cable on the back of the B&W 703's below I bought in Japan - the actual copper strand area is 5mm in diameter for each cable
. As they say in these parts 'Its proper decent like'
(The RC networks on the back on the speakers are because I've been experimenting with cable termination - different subject)