Thanks, Lena. It should get me through for a while.
Thanks, Deborah. I planned on either gluing or bolting the egg crate down to the wood ledges. I would probably get some sag, but I definitely don't think they would snap under the weight. But like I said, I'm looking into other options. I'll probably end up using birch or pine planks, spaced apart for air circulation and screwed down to the ledges.
I got it dude. I honestly should have made it wide enough for 3 tubs instead of two, but it will be good for a couple years.