Sounds to me like you're off to a good start becoming a great snake keeper.
Make sure to regulate your heat sources, whether you run a CHE, bulbs or a UTH it must be regulated. Unregulated could be fatal, and it can happen fairly quickly.
Don't waste your money on a crappy, stick-on thermometer/hygrometer either. They are wildly inaccurate and you can get a good AccuRite from Walmart for under $10.
As for covering the screen lid. I've had good success using cardboard wrapped in aluminum foil. I just cut a piece of cardboard to fit the lid and cut a hole for the lamp. I then take my time and carefully wrap the cardboard in foil and tape it nice and tight. I kinda rushed one before and had to re-do it months later. It's just easier to do it well the first time, it'll last pretty much forever. The foil will help to keep the heat and humidity in, whereas cardboard alone will actually soak moisture out of the enclosure.
Once you've got everything set up and dialed in snake keeping becomes pretty easy and you get to actually enjoy the hobby and your new pet.
When you get your next snake (you probably will...snakes and tattoos, not may people have just one!, hahahahhahahaha) you'll be prepared and have your setup up and running and dialed in before the snake comes home and avoid these learning curve headaches.
Keep up the good work getting everything right for your new snake!![]()