Just wanted to echo KMG's advice. When I was keeping my BP in a glass tank, I also keep my spotted python in glass, I used forest floor and repti bark. Personally, I think repti bark is a little easier to work with as far as spot cleaning and changing the substrate out, but forest floor seems to hold moisture a little better. The big thing is making some alterations to your enclosure. Like KMG said, making yourself some cardboard cutouts for the screen top.
You can also get these rolls of insulation from any big hardware store that are essentially two pieces of foil with bubble wrap in the middle. I use this stuff to insulate the back and sides of my glass tanks, along with some aluminum foil and duct tape on top of the screen I’ve been able to use less heat as the enclosure just retains more. Running heat sources less helped me keep humidity up especially if you’re using something like a CHE.