Sounds like you have it all figured out. Last summer when my tire blew out, in sight of nowhere Idaho, also called Challis I rented a u haul truck. I used the hook end tie downs, and slid them behind that "flat rail" piece near to where the rail is screwed to the trailer wall, then fastened the hook back onto the strap. It didn't go anywhere.

JH

"It's not what I say that's important, it's what you hear" Red Auerbach