My understanding is that Mr. Klings was living and working in California about the time I got interested in watchmaking, but unfortunately he had already moved before I had ever heard of him, otherwise I would've loved to have visited his workshop of course.
I heard a funny story about Mr. Klings from a watchmaker in SF. I can't vouch for the veracity of the story or even that I'm remembering it correctly, but reportedly he was asked to repair/restore a Patek Philippe automatic that had either a badly worn or missing ball bearing. Rather than trying to source a replacement (or perhaps after attempting to do so unsuccessfully), Mr. Klings simply made one by hand! For all you watchmakers, machinists, model-makers or otherwise craftsy people out there, you can probably imagine the difficulty of manufacturing something that small and regular (symmetrical in every regard) that requires such extreme precision, but for those of you who have no context: it would be a HUGE challenge, let me assure you.
Another story was about Mr. Klings being commissioned to add a moonphase to an AP ultrathin automatic (2120). He did so including making the dial for it from scratch, reportedly without adding any height to the case. Wow, I say.
Of course when I saw the pictures of his semi-flying tourbillon in International Wristwatch a little while later, it was clear to me this was no ordinary watchmaker performing the occasional extraordinary feat. He's someone to watch for sure.
Suitbert, thanks for the further/updated info and, Mr. Klings, please accept my apologies if I'm misremembering or otherwise misrepresenting either of these stories.