One thing I might add to this very fine post is not to forget to vacuum them out before reloading them. Like regular film holders, they get dust inside. I have a bunchof them and they are all pretty worn. I have had to gently squeeze the sides so they will still grab the film. I have been pretty successful in keeping them flat. I have one with a broken spring that I repaired with epoxy - It lasted through five reloads. I'll fix it again. If you only shoot a few and want to develop and reload the ones you shot - just remember that they are the ones on the bottom of the stack. I have done this several times and it worked fine. I can't get up to 1FPS with mine. Slow and carefull is the key - I listen carefully to the sound of the front septum shuffling to the back. You get used to the sound. A rapid shuffle is a good way to bend and malfunction. I lost a pack of color sheets in one from being to quick with it. A $12 lesson. I gently push on the groundglass to be shure not to let the pack shift while advancing the next frame. - They are certainly worth the effort though! - Frank