The best for humidity by far is cypress. But you need to be careful cause most of the cypress you find at nurserys are cypress blends which you dont want so you have to make sure its 100% cypress. Also cypress for landscaping is real chunky so you want to find a good shredded cypress like kambark. Now the easiest and most sterile of substrates is going to paper. Either news paper, corugated wrap etc. These are the easiest for cleaning and for a sterile environment. Glass enclosures are the hardest to hold heat and humidity so you have to be inventive in holding humidity such as blocking the top, insulating sides etc. What i would do is get some foam panels from home depot and cover the outside of the tank on the sides and back and 3/4 of the top. It may not look the nicest but its hard to get the best of both worlds with glass enclosures.