I have a hand-held shot on a sailboat where the sailor is looking out at a "fantastical" sky and ocean. The shot's hand-held and the boat is moving with the waves. I need to match the motion and put in water and sky with a horizon. The horizon will move with the handheld motion of the camera, but won't really move as much with the boat. I'm thinking about tracking the boat and using an expression to have the bg move at about 25-percent of the boat motion. I just wanted to ask if there's a tried and true technique for doing this. Why reinvent the wheel?