If you're up for spending a little money ($30 or so) you can throw out the screen top and make yourself a solid top out of Plexiglass. I did this with both of my tanks that are now converted to snake tanks. Humidity and heat stay in better and you have the shop cut a circular hole so you can attach screen and use a lamp if you like. You can also have them drill a few 1/4" air holes for circulation or do it yourself at home.

It's also pretty much escape proof if you remember to close the latches. I have one more tank that, if I keep using it, will be converted, too. I really like the look and the convenience.