Short version/answers first:
Neotech and Oyaide both make quality stuff.
There’s little technical/objective merit in worrying about these things for very short cable runs, so I’d buy whatever is reasonably priced and functionally convenient for the application.
Well, I’ve no experience with his products so I cannot comment there.
Reading the details on his cable there is at least one blatantly false claim (that the wire has no resistance), and most of the “theoretical” or “scientific” copy seems to have been lifted straight off the wire-manufacturer’s product pages:
All I can say to that is “bullshit” … it absolutely has electrical resistance. If it didn’t we’d be talking about room-temperature super-conductors and this company wouldn’t be fannying about peddling wire to audiophiles …
Whether the presence of that claim is just down to lack of attention to detail, lack of understanding, or something less innocent I can’t say.
I use high-purity OCC wire in my own cable builds.
The raw wire might be.
But a cable is more than it’s raw wire.
These appear to be straight, unshielded, runs of wire which is about the simplest thing you can build (e.g. absolutely no noise/EM rejection/shielding). I very much doubt there will be an audible difference between those and the stock cables, and if there’s a measurable one I doubt a) that the seller has the equipment to tell (it’s very expensive and rather specialist) and b) I wouldn’t bet on it being better numbers than the Focal ones.
However, they will almost certainly be easier to live with than the stock Focal cables, which are are something of an ergonomic disaster.
I sell my cables on the basis of convenience (modularity), quality parts, and actual measurements. I don’t make specific claims about their sound*.
*Except in the case of the SR1a cable, where the frequency shaping circuit in the interface is sensitive to the impedance of the load and even fractions of an ohm shift the treble response measurably. But you need special equipment/techniques to measure resistances that small.