i say go for it. it's nice to save a few bucks if u can.
eight 28quart tubs? that's two 28quart tubs per shelf. so that means it can fit a 28quart-plus, up to one 56quart tub if u can find one with the appropriate dimensions.
Edit: it is only 4 shelfs right? i assume so b/c there's only 4 within the frame of the pix.