I casually research this topic once in a while, and so far, have not seen high temperature superconductors emerge from either the laboratory or short haul pilot projects. Is this technology close to widespread commercial use?
However, as we already know, the superconductivity currently starts only at low temps and I think the wires are limited by a maximum current (max field density?)
If you handle the spool, NEVER lose the beginning of the wire, always fixate it, otherwise there might be a knots after some unspooling, then you might need to buy a new one.