Bullmaster like tube

[Pumping Now]

To be that packed that a Bullmaster (Standard or Magnum) is too small, wow. I have been thinking about the bottom side of the balls flush against the straight 5" diameter tube I made..and wondered if there is any advantage to a Monster Tube? It looks like the balls would be floating, not hitting any sides of the tube and thus would expand more easily? I notice they turn dark as if less oxygenated blood is circulating. Is that normal?

I think Monster Tube allows best expansion, BullMaster better shaping. I've gotten biggest in a sun tea jar.
Darkness could be too high a vacuum, pressing tube against groin too tight.
I let vacuum off every 5-10 minutes, let circulation flow.
Often I tie a cord from my tube to my foot. Flexing foot pulls tube away from groin...