Hello! I don't have the "dimensions," but I taper crimp in 9mm, .40, and .45ACP. I simply apply enough crimp to remove the last indications of flare on the case mouth and then add just enough to ever so slightly turn the case mouth inward. I suspect I'm leaving slightly more than half of the wall thickness
available for headspacing although many do opine that the extractor's holding the case back from the end of the chamber. Best.