I only use hides for the occasional picky eater/obviously stressed out snake. Most of the BPs in my rack dont need a hide. They all eat fine and dont seem stressed at all.

To monitor the humidity and temps, I have a "dummy tub" set up near the middle of the rack. It has everything identical to the tubs that have snakes in them except instead of a snake theres an accu-rite and my herpstat probe. The accu-rite is up against the front of the tub to give me the cool side temp and it's probe & the herpstat probe are in the back of the tub to show the warm end temp. The humidity is also shown on the accu-rite so I can just take a glance over at that tub and it will give me an idea of what the temps and humidity are like in all of the other tubs in my rack. You cant expect it to match up exactly with all of your tubs, but its pretty darn close To adjust the humidity you can modify the amount of holes in the tubs or even mist lightly if necessary. I havent had to mist mine because I waited till I had the rack running before just drilling out a bunch of holes in all of my tubs. If you drill too many you can cover them with tape though.

Hope that helps. I also hope it doesnt look like I was just rambling on and on and on...