No argument I appreciate any discussion about my designs and or methods. I am not sure if you use this kit or not, I would post a picture of it but this was my last one. The clip is usually held in by a plug type end cap that is the full internal diameter of the tube. So there is only a very thin circle of metal. The only way I could think to try the recessed clip other than changing the caps outside diameter would be to grind away the entire metal circle and epoxy the small rectangular section into the recess. I have serious doubts that the epoxy could stand the abuse a clip take constantly flexing.
If anyone has any other ideas I would be interested in hearing them.