The Fittest L Bracket with grip for the X-Pro2 does NOT work in RRS BH-55 bullhead with lever clamp. The bottom plate grooves are too thin and the Camera will slide right out of the locking clamp. Also the Grip does not fit properly to the X-Pro2 body. They need to modify the design: The grip needs to be redesigned or just removed. The Bottom plate arca swiss groove need to be thicker - like the short side bracket - which DOES work in the lever clamp. For the time being I would strongly recommend - DO NOT BUY if you use a lever clamp on a RRS bullhead.
Note the short bracket also BLOCKs the PC port - they need to modify that bracket too if you want access to the port.
Regards,
Mark