It kind of depends on the size of the enclosure. If you have at least 10-12'' overhead between the basking light and the basking area, I'd probably go with a 10.0/12% T5. It's also important that you have enough space away from the basking area that has little to no UVB and lower heat. That will allow your dragon to move around to get what they want at a given time. From there, you can make adjustments based on observed behavior. If they are basking a lot directly under the lights, you can try increasing the temps and/or moving the
UVB light slightly closer to see how they respond. If they stay to the side of the basking area and seem to favor cooler temps/lower UVB exposure, you can increase the distance to the lights a bit and see how they react.
Moved by moderator from Advanced Discussion to Enclosures.