My plastic prototype before moving on to CNC aluminum. This quick release plate or "wedge" is similar to those found in large cinema support devices like the Oconnor Europlate, Ronford Baker RBQ, or Sachtler Video30 Head.

4 solid layers on top and bottom with .65 infill for stability. You will still need to use a hand tap for a 3/8-16 capture screw to be mounted in the slot. You will also need to cut and glue rubber pads into the recessed locations on the surface, which holds your camera body in place.