This was a new design that was heavily inspired by some of the existing solutions out there, but I felt it left some room for improvement. There were some elements in the other designs that I was not a fan. This design eliminates the bottom facing flat, so that the clip easily engages with the clam shell and keep the installation pressure and clip stress to a minimum during installation. The removal of the bottom facing flat also reduces bending stress in the clip, by effectively creating a long cantilever arm. The engaging clip surface is still slightly larger than the OE geometry to ensure a solid locking engagement with the clam shell. Additional radii were also added to reduce stress when bending. The centering rails on the sides were also extended to create a slight interference and thus help stabilize the clip while you drill your bolt hole.

I would recommend a 3mm x 10mm LG bolt, but actually in my photos, I drilled out the clip for a 4mm x 10mm LG bolt, as that is all I had on hand. With the use of a 4mm bolt, I had to use needle nose pliers to hold backup on my lock nut, as I could not get a wrench or socket on it. But since you want to keep make-up torque to a minimum, this was not an issue.

This part is very small and thin, making it pretty insensitive to your infill percentage, but I set mine to 100%, but if your wall thickness is 3 or more, this will not have any significant impact. I designed this to be printed in ABS, but could likely be printed in PETG, but your latching forces will likely much lower and ABS is more rigid.

Be sure to print with the model oriented on its side so that the print layers align with the length of the clam engaging clip, otherwise your bending stress will break at a print layer.