There's a hole in the provided hinge to mount the shock to. I didn't dare mount it directly to the footbox beacuse I knew I had a 0.0% chance of getting the right location (I was right too, lol), so I made a bracket out of 1/4'' aluminum, bolted it to the footbox side, then kept drilling and tapping it for the shock ballstud until I found the right location for me. Then I made the final bracket.
I doubt there's a 1 location fits all because the hinge install will end up being unique to each build probably (at least if you want perfect gapping and flushness....it is possible if you invest the time!)