Humidity

[Dan and Kandyce]

I'm having a hard time keeping humidity up with my boa. I have a screen top on there right now, but as you know, thats no good for keeping up humidity. I can get some Lexan plexiglass waterjet cut in any shape and size I need from work, with all the cut outs I need. I was thinking about getting that cut and then siliconing it in on the outside of the screen top that way I can still use the screen to to clamp into the sides of the tank. Does this sound like a good idea or is there another aestheticaly pleasing way to do this? Also at about what percentage humidity should i keep the cage at?