Looking to build a 3 tub rack for three adult ball pythons

[tttaylorrr]

I guess i feel like only the tops need to be water proof. I think that the back and sides won't come into contact with the Humidity like the top and bottom of the shelves. But wait, whats the smallest size PVC panel that you can buy? If it's 8ft by 4ft i could make a 5 snake rack with one piece of PVC using 41Q rubbermaids. What do you think of these tubs for this project?

https://www.walmart.com/ip/Sterilite...TDGCFh_KdWUWHA

those are a nice size. my current design is based off of IRIS CB-70 tubs like AP racks. i'm about to post my thread.