Most gimbals are equipped to handle a gopro style camera, meaning the support 'tray' is oriented horizontally for the camera to sit on. Our phone or display will not be sitting on it. Reorienting the tray to act as a back plate-style mounting surface shoud be easy enough: just turn it...

However, there is an MPU attached to this plate which sends the orientation to the processing board. To get this to register correct orientation, we will have to turn it 90 degrees so when the back plate is in the upright position, the MPU sits perpendicular to the display plane.

To attach the MPU, one could 3D print an appropriate bracket, but since I have committed myself to a 'no-3D-print' build on this one, a flattened and right-angled piece of PVC screwed to the back plate and some hot glue will do just fine!

There are a variety of kits for mounting almost any small screen to the back plate and this will have to mounted after a final screen is selected for this project. Mounting can be bolts, straps or my personal favorite, zip ties!