Welcome to the forum Ifan. Your Exo Terra is perfect for frogs, especially tree frogs. That tank is what a lot of us use here. As far as frogs go check out the care articles on the left. The Whites Tree Frog, the Red Eye Leaf Frog and the American Green tree frog are all good frogs to start with. As far as the humidity is concerned using live plants with the proper ground cover will help with that. You can also cover up a portion of the screen on top to keep in some moisture. Hand misting in the morning and at night is usually good enough to keep your humidity in the proper range. If you can get your tank set up before you get your frog that way you can make sure you are meeting the frogs environmental needs consistently. Good luck with your decision. Take a look in the photo albums that will give you some ideas.