https://en.wikipedia.org/wiki/C._V._Boys
Especially: "On the Production, Properties, and some suggested Uses of the Finest Threads." 1887
https://zenodo.org/record/1431517/files/article.pdf
This is a very entertaining read, and highly recommended.
He produced extremely fine threads of glass, quartz, etc. finer than the visible light diffraction limit. (Which he would use to construct sensitive torsion balances)
He was inspired by Peles Hair. (Volcanoes grow hair too...). He first describes electro-spinning and its limitations (uncontrolled growth of hair which mattes together).
How did he do it? He used a miniature crossbow, modified so he could trigger it by foot pedal, leaving his hands free to work.
He would first produce a small thin section by more conventional means, glue one end to a fine dart or arrow (a piece of straw really).
Then he would use a blowpipe and melt the piece of say quartz until a bead forms, at which point he would trigger the cross bow.
As the arrow of straw shot away it draws the bead of melt to a long fine thread.
Perhaps this can be modernized to vacuum or inert atmosphere, melt the quasi LK-99 sample until it beads, then shoot away. Rewind the resulting thread and re-anneal any non-superconductive segments.
Another use-case for the Baltimore shot tower (https://en.wikipedia.org/wiki/Phoenix_Shot_Tower)
1: Superconductivity becomes widely confirmed
2: Reproducibility remains microscopic
Imagine a game of rolling a collection of n dice (normal 6 sided), where the player wins if all N dice are 4 or higher (probability 1/2 for a single dice).
Then the probability of a lucky roll is P = (½)ⁿ
So the smaller the collection of dice the more likely a lucky roll becomes.
Consider a hypothetical continuous production method of LK-99, where the fraction of wire in superconducting arrangement is a function of its thickness, more likely if thinner.
Could one simply re-anneal (and possibly re-quench) a short non-superconducting section until we get lucky, then proceed to the next non-superconducting section?
"Lucky annealing" fortune cookies?