I attempts to turn the FX6 into a shoulder camera I am seeing a lot of people removing the FX6’s handgrip from the side of the camera and then attaching an extension arm to the camera body where the hand grip normally attaches, perhaps either directly with a dedicated arm or by  fitting a rosette to the camera body.

I strongly recommend you do not do this! 

A long arm increases the amount of force that can be applied to the body of the camera and it wasn’t designed to take the forces an arm places on it. Especially if the camera is loaded up with other accessories such as monitors, V-Lock adapters or a base plate. There have been several instances of the camera body fracturing around the hand grip mount when an extension arm has been used. Replacing the camera body is not cheap and it is unlikely to be covered under any warranty as it wasn’t designed to be used this way.

Instead mount the arm to a base plate, there are many FX6 base plates that include a suitable rosette for arms and other accessories.