I have made some changes to the original which improves repeatability and mechanical reliability.
I'm using red 40-A-L o-rings on the bottom of the piezo, with about 20% compression by tightening the 4x mounting screws. I've modified the mount so that the o-ring compression is enough to keep the hotend steady but the contact on the peizo is much lighter than before.
The mount should be printed in 0.1mm layer height to ensure the distance between the o-rings and contact ring is accurate.
My coordinate system is flipped so the stl is shown upside down, just flip it in your slicer.
I used a 0.25mm nozzle, 0.4 should be fine.