Let me tell you what i meant exactly with 50cm minimum height for an adult according to the experience that i had. My adult 4 feet male was housed in a cage that is in inches: 40 long, 20 deep, 20 high. 20 inches=50cm. This is the absolut minimum tank size for an animal that size if you want to keep it in a proper way. Now if you want to reduce the height you need to compensate that in adding more floor space.