Hi and welcome to the forum. First off, check out the three threads below because they will answer a lot of your questions.
How to setup a 20 gallon glass tank:
http://ball-pythons.net/forums/showthread.php?t=201740
Shedding Process:
http://ball-pythons.net/forums/showthread.php?t=28794
Ball Python Care Sheet:
http://ball-pythons.net/forums/showthread.php?t=127203
The first thing I want to address is a NEED for a thermostat for your UTH. Without a thermostat, you're running a huge risk of burning your snake. The reason we use a thermostat for a UTH is to control how hot it gets. An unregulated UTH can get very hot.
A thermostat for your UTH would not eliminate a need for a heat lamp. UTH provides belly heat while the heat lamp provides ambient heat.
On the humidity issue, I'd suggest using coco husk as bedding. Also, I would suggest closing off the top of your screen with foil. That will trap your humidity better. You'll find how to do that in the tank setup thread.
On the feeding part, wait a week for your BP to get used to his environment and try to feed him again next week.
Hope this helps. Don't be afraid to ask more questions if I didnt answer something or if you need clarification. The whole point of this is forum is to learn.
I'm also writing this mini essay on my phone so I might have missed a few things.
Sent using Tapatalk