Well i've decided to setup a leopard gecko terrarium for my desk. I'm going to use a 10 gallon tank for now since the leopards at petco aren't very big (between 3-5"). I have a 20 gallon long i can upgrade them to later on. Today I bought an undertank heater for the 10. Almost every care sheet ive read online says to use paper towels with small leopards but the heater says not to use them. What should i do? Should i use some felt or something instead? Would the UTH be able to heat the entire tank or should i use some form of overhead heating also? How long would i be able to keep 2-3 small leopards in the 10 gallon? Can you sex leopards at 3 inches?