No matter the temperatures you achieve with the MVB, never move it any closer then 12" to the dragon. I'm not talking about 12" to the basking spot, but 12" to the top of the animal. This means you may need a secondary heat bulb, as even the smallest adult dragons can sit up 3-4" (putting the bulb 16" away from the basking spot). I firmly believe the lack of sufficient heat caused people to move the bulbs closer, and this in turn was responsible for many of the reported issues with MVB's. I'll never be able to prove that however.
Anyways, good luck.
Anyways, good luck.