[ultravista]

Robert - thanks for the photos. It makes sense now!

Now I have to figure out how do to this effectively with a glass Big Mouth Bubbler (no port of course).

[Robert]

You won't be the first to do this.  Basically you start with two holes in the lid...helpful, right? There are surely posts and videos out there to help.  One thing to remember:  with glass, never apply more than 1-2psi.  I used to use glass carboys, and the paranoia about this was one reason I switched.  But just be careful, even that low pressure is plenty to move beer -- when you think about it, it's like a lot of weight plunging down on your beer.  Good luck with the project!