Never used the clips on both 35mm and 120 film and reels. I just stuck the film into the center of the reel and started winding. In my experience, as Ed said, if the film is not centered under the clip, it will kink when winding. And once the edge of the film is kinked, it becomes a PiA to salvage, as the kinked edge will make it HARD to get the film between the wires. So even on my reels with clips, I ignore the clips.