Finding a specific cable

Unfortunately, I need a 40’ run for. my speaker cables or interconnects (one or the other). I’m looking for the best options.

Interconnects should take up most of the distance.

Many esoteric speaker cables have LC properties that can wreak havoc with some amplifiers, especially with longer lengths. Eight feet is more than enough length for most home systems.

IF you need flat, Goertz made nice sounding ones. For reasonably cost long cables, do what the pros do: balanced Mogami long interconnects. Keep speaker cables short.

Received wisdom is that for long runs you must use balanced ICs.

Still, also check out these:

https://audioenvy.com/product/speaker/sp12/

Balanced only pay benefits is noisy environments. Improperly done, they can be worse that unbalanced.