We didn't hang any weights because we used books. I was so surprised it held 20+ books on top. We took off the top so it would be flat ground, so the books can hold it.
It has to be strong and sturdy so it will fit the books on it. And if you are going to make a box that' s also going to help it stand up. Like I said in the beginning my structure held 20+ books, which is16kg.