Thanks for the pics! I'm wondering if the C clips that you got were larger than the ones that I bought, or just pre-stretched since they had already been installed. Also, when I disassembled my original material from the frame, I found a different shaped metal piece was used. It was "V" shaped and held the materialinside the frame. I've attached a pic showing an original piece and a new C clip side by side. The original piece is on the left. I also attached a pic showing the original piece still in the seat cushion frame (the frame is upside down in the pic).
So I'm wondering if I should try to force the new clip over the material and frame or wrap the material around the frame and use the new clips to wedge it into the frame the way it was originally done?