I have next to no knowledge of these, other than confirming that they are A Thing - I fell for something like this a couple of years ago, it being a converted Junghans pocket watch. It's rather well done - the lugs are welded-on seamlessly, the obvious tell being they take springbars! Aside from being a bit big at 50mm it's a good watch, keeps good time, holds a wind for ~36 hours, the movement's perfect. I rarely wear it because the crystal is pretty fragile compared with modern watches, and it has zero waterproofing. Annoyed with myself for falling for it - it's been a steep learning curve!