Another thing about Topsy-Turvy is Leigh's genius in staging the spark - the moment of inspiration - that kicks off the new opera and the rest of the film.
He plays around a bit with the actual chronology of the Japanese Exhibition in London and the sword, etc., all for perfect dramatic purposes. He puts it right up there on the screen -- the event and moment on which the whole story turns, and it's utterly thrilling. The genius part of it is that it's not overdone, either by actor Jim Broadbent, or the music, or anything. It's a magical moment.
He then jumps out of time and cuts right to a scene from the finished production. We're a whole hour into the movie when this moment finally happens, and it's a quick gift to the audience that we see what this all came to...before he then jumps back into the "present" and the collaborative process actually gets underway. The pacing in this thing is unlike anything else. And the extended "dry" rehearsal scene in which Gilbert begins shaping the performances of Pooh, Pitti, and Koko, is captivating to the nth degree.