Question 1: When I was researching how to take care of a Ball Python (before I got one), I never read that I would need a heat lamp to maintain my temps on the cold side!
They're currently fluctuating between 72F and 76F. They're supposed to be around 80F, if I'm correct. Should I get a heat lamp, ceramic heat emitter, or what? If I do, will I need a thermostat for that, too? I'm really confused, because I haven't heard anything about that before. If it's relevant, I have an Exo Terra terrarium, with a screen top and ventilation on the front. I have a damp towel over the cold side of the terrarium to keep the humidity up. Humidity is at about 60%, and the hot side is at 90F.
Question 2: Should I be using terrarium carpet or a liner? I'm only using aspen shavings now. Again, in all the care sheets I read, it didn't mention using a liner, so I'm not sure.

Let me know if you need more info to answer the questions.