Wattage is going to be determined by the amount of heat you need to generate. Humidity is hard to keep correct using bulbs in a tank. I have never heard of a muti-level tank setup for a BP. Please read the sticky thread here on a tank setup. Be aware that ball pythons are mostly terrestrial snakes. Boys will climb a little, but it would be very rare for an adult girl. A lot of activity, especially during the day for a ball often times points to a husbandry problem.