OK, Built one this weekend and it worked like gangbusters. The paper bag membrane works very well. I also used male and female threaded adapters to hold it in place as recommended elsewhere on here.
I had a double discharge type air pump and simply tee'd the lines together to a surplus ice maker water valve which worked well to modulate air flow.
I glued the bottom cap onto a 2X3 reducing coupling for a stable base.
Overall, very satisfied and I want to thank you guys for the help and guidance.
Best regards all.