I do the same thing, I only have tubs with the locking lids there is no rack system for me just yet. I have three BPs each in their own tub, Right now My two new additions are in 66qt tubs because they are used to smaller spaces so I want to work them up slowly to the 110 qt that my first BP is in. He adjusted quickly but I don't want to overwhelm these two because they are used to having less space because they came directly from the breeder. My other one is from the same breeder but he was sold to a local mom and pop pet store where I got him so he is used to more space. Each one of my tubs has a heating pad under it connected to a thermostat and it works wonderfully the temps and humidity stay right where it needs to and as long as they are locked and secured there shouldn't be an issue with just tubs. I hope to have more tubs in the immediate future with a lot of snakes too. I have pics from the creation of the tub for my first snake. It really is pretty simple to do. Part of the reason I personally use tubs is because my BPs aren't really up for display, I personally don't have to see them to be happy with them there. The tubs are all semi clear so they get light and I CAN see them but there aren't too many people that I would show them to.