Turned these up on the lathe, any durable plastic will do, I used nylon. The dimensions are, from the screw head end: .600 for.250 .815 for.090 .950 for.090 .650 for.250
Drill .328 hole, insert 10-24 coupling nut, use two 10-24 x 3/8 screws.
Use the original locking clip on the inside of the light.