Its often hard to help on this site since none of us are there to see it. I thought my 40 gallon was big. They made some money off you. If you put allot of fake plants and cover in the tank it will help make you BP feel safe and secure and make it less stressed. You can give it several hides too.

For the substrate I would let it dry out. I like Forest Floor shavings for my BP. But for my hognose I like the Eco-Earth b/c she burrows. But I don't keep the Eco-Earth wet after it dries out. You could be asking for mold to grow.

IMO you should stir it often to prevent mold and help it dry, then just leave it dry. Misting the tank should keep your humidity up, but like stated above during a shed it should be higher. Another good way to aid the humidity is to mist the cover and plants in the tank. Your BP will often times drink the water beads on the leaves.

Do you know your humidity? What are you using to measure it, digital/analog?