I recently got me a Caddx Walnut, and needed a mount, and there don't seem to be that many out there, so I made my own.
Attribution: I took the GoPro prongs from MrSwarets Session 5 Mount (linked on Thingiverse)
the rest is my own design.
I'll probably add a few fixed-angle versions for the frames I most commonly fly in the future. I've printed all prototypes and this one is pretty standard TPU - don't use any hard plastics, it won't work.