your going to have sagging in the center unless you make supports to fit in between the shelves. i have one i made that will hold 16 28 qt tubs or 8 41 qt tubs and it started sagging within 6 months. you will need to make removable supports that will divide the shelves when using the 28 qt tubs. when using the 41 qt tubs they may get tight from the sagging.
adam jeffery
with melamine and 41 qt tubs its best to make it to accept the tubs the long way, but then you cant use the 28 qts at the same time