Just to let you know its always good to get the tubs BEFORE you build the rack. You may not run into problems this time or you may.
I built a 5 high rack out of the 1655 sterilite 28 QT tubs. Well.. I needed another rack.. So what do i do? Went to home depot got all the wood cut, built the rack, heated it. Than since i always get the sterilite 1655 28 QT tubs from Target i was just going to go there to get some. WRONG! They had the other version of the 28 QT tubs, which i believe are different measurements. Aka wont fit into the rack. After driving to 3 different Targets i found the tubs!
Hopefully u can find the same exact tubs to go along with the rack your building, if not! Then your going to have some problems!