Finally, a seven-string I can see the point of. This makes more sense than a double-neck. This guy has a lot of very entertaining videos and he's a hell of a player.
Unfortunately, this instrument was discontinued in 2019. Here are some pictures I had saved:
Well, I ordered up one of these headless bridges for about $60 shipped, and after three weeks, here it is:
As you can see, I disassembled one of the gear mechanisms. The one-piece gear and spool appear to be solid brass, held in the bracket with a c-clip. The gears actually work surprisingly well, smooth, with just a little slop that would disappear under string tension. Everything is also lubricated, which I did not expect from China. I am surprised, the quality of materials and design of this unit is much better than I expected. You can see how the knobs pull out on the shafts for easier adjustment.