I tested the setup out this weekend. It worked great. No rattle noises that I could hear over the engine noise. Everthing stayed very secure. The storage box rocks a tad bit back and forth over really bad whoops. So eventually I’m going to get a piece of metal flat stock that’s wide. To run the width of the box under the washers. That will stiffen the box up and stop that. Honestly I could ignore it but I am a perfectionist thanks for all the feedback so far!
Here are some pictures from my outing yesterday. The storage box holds a Colman classic cook stove perfectly. I mean like a glove! The pack out coolers hold a lot. 15 water bottles for one cooler. The other one held a lot of food.