I messed up....

Totally agree. Improvise, Adapt and Overcome... I was thinking of drilling a hole in some 1/8 plate, then cutting it in half. Thin it out along the inside edge and use that as a wedge clamping it to the press.
Yes I was thinking abusing the bottom of it as a template to draw a hole and cut it out of the piece of metal and then cut the metal and half straight through the hole so you can bring both sides in and clamp it like two half circles that come make a full circle..