I recently created a custom enclosure for Stella. I setup a basking limb that got about 8 inches from the UVB and was 100 degrees with a digital thermometer. Well she wouldnt bask for long, and kept climbing under the tree. Then I started looking at the light setup in many enclosures. It seems as thought the basking site is seperate from the UVB basking area? So now I have her basking site setup, then I have a seperate tree that gets about 10 inches from the UVB. Is this exceptable? the enclosure is 48" long and I have a 36" reptisun 10.0 centered on the top.
The UVB is a HUGE, FAT bulb. It almost didnt fit in the ballast (matter of fact the bulb wouldnt fit if i used the screws to fasten to the ceiling) the box said to have it 12" from the reptile.
The Reptisun 10.0 is acceptable at 6-8 inches last I heard. My advice is to keep the basking near the UV source allowing your dragon to get adequate UV while basking. How old is your dragon? Some dragons are different in the way of temperature. Some like it hotter while some like it cooler then others. You could try to decrease the wattage of the basking bulb or add a dimmer switch to it allowing you to fine tune the temperature to that particular dragons preferences.