I got to ask pro pumpers on this subject. What's the high pressure zone you're going into after years of pumping in terms of inHg (forget mmHg). I tend to enter in between 10 and 13 inHg for the Bathmate, and in the old days, up to 15 inHg using Doc Johnson cylinder. 15 inHg was the high end for me as the vac forced blood and fluid blisters to form after the 4th session of 5 minutes.
I tried to break it down to 1 minute per session and span out to 20 sessions, but there was no feeling of yanking fatigue like the 5 minutes of dynamic pressure (up and down from 10 to 15inHg). One of my smaller capillaries burst under vac pressure when I was reaching 18 inHg after 2 years of pumping. So this is something for me to research on the pump vets. The human cadaver's penile corpus cavernosa had been recorded to reach around 500 inHg before rupturing, but that's just the corpus caversona. The veins, arteries, and capillaries are a lot more sensitive under extreme pressure, estimated around 12 inHg before becoming deformed/malformed and entering rupturing phases. The arteries and veins hear the heart can go as high as 20 inHg, but not so much for the further reaches like the brain, the arms, and below the belly.