I know this is a little off the subject, but I am using the carbinge keeper Idea. I originally got the idea from a multiple Lancair builder some years back. I took a 10/32 X 1/2 stainless set screw and centered drilled the set screw with a #40 drill. Then silver soldered a stainless hinge pin to the set screw.
I took a 10/32 rivnut and removed the head. I fiberglassed the rivnut into the cowling. The set screw threads into the rivnut.
For the hinge I used a MS 20001-6 and offset the hinge below the cowl seam.

Aaron