For those who didn't know, you can use follower commands to have them pick up items and loot containers/bodies even past their encumbrance limit. Some people have said that if you make them pick up items off the ground, they can't be in stacks or they'll be lost forever. Does this also apply to when they pick up stacked items in containers, or can you just stick 2000 pounds of god-knows-what in a chest, stacked in all sorts of different quantities, and they will remain in the follower's inventory for however long you leave it there?

I'm not sure, I attempted this with Lydia a few times and it seemed to work well enough, only some items would simply vanish but still reduce her carry weight for some reason.