On my little toy hauler I used through bolts and big ass custom washers. (you'll need spacers to get any sort of tight on it due to interior vs exterior wall space/squish.)
That awning is NEVER coming loose again.
I Preemptively did the ladder also.
So I reach in the junk drawer just this minute for something and pulled this out blind. I haven't seen it in maybe ten years.
The nitrous toy hauler had a polished diamond plate theme.....
I wish we had been typing about gold bars instead of this damn washer....