Use light pressure and start at speed one on the PE8. Do a pass at speed one and then check your progress. If you're not in a hurry, and if you don't have prior experience with the PE8, it's a good idea to use the tool at the lowest speed setting for just a short amount of time, check your progress and then keep repeating until you're happy. You can always remove more clear coat, but you can't add it back once it's gone.
The tool is super useful, you just have to be mindful about heat being generated on the panel (especially on plastic parts) and how quickly clear coat is being removed in such a small area.