Maintaining Humidity

[Nicolak]

Hello,

I just got my new Ball Python. The humidity seems to stay at 50-55%, is this alright? If not what are some good ways to increase the humidity?

I am using Aspen substrate, small heat tape for the warm side & a heat lamp (red bulb 100w). Tank is 36"x12" (height 17"), 33 gallon aquarium.
A large size water dish. The Ball python is approx 2 feet. Also I have a towel covering the top where the heat lamp is not. (I have left enough room for air to get in)

A few other questions, just based on your personal experience.
How thick should the substrate be from the bottom?
What is a good basking temperature (90F?), what is considered "too hot"?
What is the coldest it can get on the cold side for it to be considered "too cold"?

I have heard different opinions: Do Ball Pythons like to climb?

Also, what are some signs when a ball python is about to go into a shed?

Thanks