I would go with at least a 10g tank if you are going to use that, I really think you would be best suited to start out with an non screen top enclosure because it is a pain in the butt to keep the humidity and heat in there. You should also have at least 2 hides, one on the warm side and one on the cool side so your snake can go where it wants to regulate it's body temp. You don't want your snake to have to choose between warmth and feeling secure because that can cause stress. Definitely agree that a thermostat is required for a UTH. Welcome to the forum.