I have done some revisions to the opener. I have replaced the larger opener with a smaller one. the smaller contact area lets the clay be opened with less force. The plunger is still bulky enough to prevent any bending as it opens the clay.

my work during these revisions has uncovered three area of interest.

1. lowering the opening pressure has lessened the dimple that appears when first opening the clay.
2.  the rod that connects the plunger to the opener arm must be kept as close as possible to 90 degrees to prevent the arm from drifting off center as it is adjusted.
3.  the opener can readily produce a flat compressed bottom with the exception of a dimple that is caused by opening.

My current goals are to reduce the dimple by reducing the twisting, introduce a way to attach a sponge or other padded surface to the plunger, and a way to introduce repeatability.