greenlawnracing wrote:
Is what I circled what I need then? Number one, two just in case it is tight, and five to clamp it all?
the uppermost circled one (in your picture) is the one you need. It has one end with two "fins" (to be grabbed by Go-Pro style mount) and another end with a single fin (compatible with Garmin's hardware)
i would not recommend the 3D-printed adapter, at least not the long adapter (this one: https://www.ebay.com/...2:g:Jr0AAOSwofxUktlq). Had two of those, and both broke when I rode over some rough roads. Furthermore, due to construction of those adapters, I literally had to break it apart so that the parts attached to it could be wrangled free.
One used to be able to buy the mounting bracket, and I believe those came with additional adapters like the one shown in your photo