I am designing a 360-degree 120 film rotational panoramic camera (for my own use, not commercially) and I need some help regarding film transport. I am using two motors, one for camera rotation and one for film advance, but I am not sure how to get a consistent film advance speed. If I drive the take up spool then I assume the film transport speed will slow as the empty spool winds up the film. I have seen images of the Roundshot 220VR and I see it has a drum that the film wraps around, does the drum actually drive the film or just tension it? And is the take up spool (also) driven, and if so does the speed vary as the film winds up? Does it actually make a difference in reality? Thanks!