I have an old box kite that’s held together with fiberglass spars and rubber joints. I cut a few spars down with a rotary tool to fit the peculiarities of my camera. I anchored two rubber joints to the tripod mount of the camera. The electronics pouch (mini binocular case) is held in place by two spars through the belt loop and pressure holding it against the camera.
Next, I’m going to add a downrigger clip and line release to the top. That will connect the bracket to the kite line. If this version of the bracket still looks good to me in a few days, I’ll glue it all together with super glue.