I love what you are doing with the Rec Deck. But I don't understand why you can't combine the back of the set as built (the catwalks along the windows) with the front (a stage at the lower level). The screen? That can fold down from the ceiling, be a virtual screen, or just sit free floating above the stage and in front of the catwalks.
It seems that the great choice of harmonizing Probert's concept with what was filmed is undercut by having an unfunctional theater setting where the screen is back where the projector sits.