Knowing what I know now and having a truck with a gooseneck hitch in the bed I would've went with the Reese Goosebox pin box. I tried the MR pin box and while it will relieve some chucking it won't relieve all of it. Even MR says it won't relieve 100% of chucking.
Shocks and a MR3000 will help a little but won't cure. IMO nothing cures it 100%.
You either have it or your don't. Problem with looking for cures is everyone tows a different 5er with a different truck.
LOL, I always though the best way to buy a 5er and truck is to ask the question, "Who doesn't have chucking"?. Then look at what they own and go buy that.
If it were me I would sell the Andersen and get a gooseneck pin box with a bag. It's going to be as good as the MR and now you don't have to deal with the Andersen in the bed. Once you're unhitch you bed is clear.