Loc: New York, NY
16J on the largest 18mm spot size is a pretty high setting. The max is 20J on 18mm. If the spot size is smaller than that (i.e. 15mm, 12mm, etc), the overall power decreases greatly. So you should try to get treated at 18mm spot size if possible. Of course, you need to make sure your skin can handle these settings.
What specific areas are you treating? Is the hair coarse?
If you have an ethnic background, you still have underlying pigment even if you look light. So keep that in mind.