Question about rack

ok, not sure if this will work. I have several stone tiles that are bout 1/4 of an inch thick, can I just put those on each shelf and then put the tubs on top of them? It would make the tubs almost flush with the shelf above it, but it would keep them from lying directly on the heat tape.

Ok, I just checked and apparently Sterilite has several different 28qt tubs with different dimensions. The ones I got are 5 7/8 inches tall, and then there is another 28 qt that is 6 1/4 inches tall. I just need to return these tubs and get those. That will leave less than 1/8 inch, and that is more than ok with me. Problem solved.