Greetings all,
I stumbled across a free program that was released recently called
"jorgan" that allows you to pick and choose registrations ahead of and
on the fly for your performance. It was at a site that I had visited
before but must have been added to it not too long ago. The address is
http://meiers.net/sven/jorgan
It is set up for classical organ but could be adapted to theater
organ. I have not had time to try it yet in either way but it looks
very good from the screen shots and I am sure it will be helpful to
many virtual/midi organ players.