https://youtu.be/wVa4nZzwgIg
Printable View
Very clever, I like the tapered self-adjusting clamps. I would humbly suggest two refinements.
Make a flat on the edge of the square block that fits into the interior corner of the box. This would hopefully prohibit glue squeeze out from gluing the jig to the project.
Thoroughly wax the sides of the square block so that glue will not adhere to them.