Since he is using the cage humidifier than I would think it's safe to say their humidity is low.
I used one for over a year when I kept my bp in a glass tank. Kept it a nice even 55%. Had it running along the back wall of the tank.

Sometimes if you take your bp out on a regular basis and just let him get use to you then they will stop the hissing and biting one they realize your not a threat. But you may incounter a bite or two along the way