Shimming camper to minimize side to side movement

Some good points. I think it might end up being a combination of solutions.

I have a sprayed in bed liner and no mat. Currently, the camper rides on a 2x4 platform made by the previous owner. I am only using it because I need the space to use the brophy mounts. Once I finally convert over to either happijac or torklift I will no longer need the riser for that purpose. Then I'll have to see if I need one to clear the cab on the truck.