+1 for the CG and +2 on the customer service. John also sent me extra parts when I had problems. I found that the best combination is a curved main piece and a medium curved clamp. If either of the parts is flat it seems to slip off too easily. Apart from that it is brilliant; I love feeling snugged down in my seat and not worrying about sliding around.
Find them at http://www.cg-lock.com/