After an epic battle with my TurboCAD_2016 ('TC'), I managed to remove several extraneous boxes from the timber truss, scale to suit. Or, 'sufficiently plausible'...
TC's OBJ export is rather like Poser's FBX import: 'YMMV'. And, there may be 'artifacts'...
The windows were a 4x7 matrix of fixed glazing squares, plus a four-in-row top-hinged clerestory set. Another epic battle with 'TC' removed the matrix glazing, cut one window from row. For reasons beyond my wits, the LH of four windows would not split out cleanly. Artifacts ensued. The second was okay.
But, of course, it was now 'fixed' in position. So, back to the drawing board, uh, app.
Second time around, I managed to export frame, glazing frame and glazing as separate OBJs. I used Poser's 'show origin' etc tools to move 'object centre' of glazing frame to logical hinge line. Scaled and parented glazing to this, scaled and parented these to the frame. Scaled this such two would fit between trusses. Can tilt by ~20º.
Now, the hair-tear: I can 'duplicate' a truss, and it is identical to original. But, when I duplicate window, it is 'fixed' rather than having its tilting glazing frame and glazing along for the ride...
I've obviously missed something, some-where, but...
The spiral stairs ? Rather than try to edit them, they'll set the balcony height. I've found some nice, simple 'kneeling pews' to populate that. I'll position some more pews before and after the 'labyrinth', the latter facing inwards to a prial of lecterns...
