I keep my BP in a 20 gal long. I use a 60 watt red nocturnal heat bulb that is on for 24 hrs a day. I also use a UTH which is kept on a lamp dimmer to maintain 90 degrees in the warm side hide. I would only use the UTH if I could, but without the light and only the UTH my ambiant drops into the 70's.
For the screen lid, I duct taped it 3/4's of the way and the uncovered 1/4 is where the heat lamp sits.
I mist my tank whenever I see that humidity is below 45% and the tape on the screen lid helps keep it in for a while.
If you cant get temp/humidy right, I would suggest using a tub as they are much easier to hold in temp/humidity.


Hope this helps,