I would recommend doing something like what I did in this photo. I originally just did a simple hook like you posted, but some very high winds bent it, and it was somewhat loose - I still don’t know how it stayed in.
I cut a piece of angled steel, drilled holes, and painted with white Plastidip. Then used some nylon spacers with the marine hook. I have not had any issues at all, it’s been 7 months and they’re rock solid.
I tried the exciters, it was neat…but not great sound fidelity. But still a fun little concept which definitely has uses.