I confess to knowing nothing about the theatre organ, but I have huge respect for people that play it and the repertoire involved (or improvisation? I have no idea haha!). When I tell general folk that I play the organ, most think of the theatre organ first before church organs...or those spinet organs that were once popular in people's homes. Recently Fraser Gartshore has been pestering me to give the theatre organ a crack so this is my lame attempt. If you'd like to hear Fraser play some really entertaining theatre organ, have a listen to his latest video: 
Paramount 310 Hauptwerk sample set: http://www.paramountorganworks.com/