I have a similar issue. What I have added is just humid hides. They spend a large period of the time in their hides so makes sure it stays moist there. I prefer moss for this purpose but paper towel will work. I have also changed to coconut fiber for substrate. It looks nice and holds water pretty well. I only have one screen setup for my large normal so this is the only one i have to deal with. It has been working for the past three years though so i would say its a success.