I’m using a Technec Jackreel F4. I’ve created some 3d printed insert pieces that allow someone to integrate the fathom X tether board into the back frame of the reel holder, and to internally mount the slipring so that you can rout the static lead back through the bearing shaft hollow space to the box. I haven’t published the files yet as there are a few pieces in the works that aren’t done yet ( the cable feed rollers, a USB / net / video cable management strain relief thingy, and a "piece that holds the end of your tether with the seacon micro-wetcon 8 pin quick disconnect and the cable anchor point (McMaster-Carr)
You can see the pictures of it so far here: