Using scrap ¼" plywood, cut two 2"-square vertical struts and a 2¾"×6½" test section floor. Cut the back plate 2"×2½" tall, and lighten it with a large cutout, because weight not centered in the pivoting mechanism will tend to fall backward and inflate very small measurements. Glue a ½"×¾" block to the lower-center-back of the plate; this spacer is what presses against the force beam.