It occurred to me that having it hygrometer controlled would also reduce the odds of bellyrot and/or mold in the substrate as well.
Upon considering it further, I can/may have to set nozzle diameter or use a ball valve to adjust flow to each tub as they will be stacked, so I could run into issues with extreme humidity at the bottom and insufficient at the top.
I've also been stewing on how to set it up so I don't have issues with a large hole at the rear of the tub for a snake to escape through, either into the open if the tub is pulled out, or into the tube from the humidifeir. I think a metal screen could cause issues with condensation on the screen because of their density. I may try a foot screen, or just an end cap with holes drilled in it. The hole in the tub will be just large enough for the pipe to fit through, with the screen or cap secured to the inside of the tube and acting as a socket for the pipe when the tub is slid back into the rack.