Nice! I always wondered about adequate ventilation in deep tubs like those. Now I see that it can be done. And you could even stack them with breathability..
I highly recommend the WoodyPet pellets. I started using them a week and 2 days ago and they are not even ready to change just yet.. and the only odor you get is the woodsy smell of the pellets themselves.. awesome stuff. I do add in a few socks for the rats to nest with, as pellets can't be all that comfy