Actually that's as high as you should go, if anything I would lower to 1.5mm. What's the wick configuration? Do you run the wick tails just down to channels? Or run them across ledge? Sometimes if wick tails are to big and puffy you can get a wettish kind of vape.
I agree here with the wick tails. I don't know if you call it over saturation or over wicking, or both, but too much wick means too much liquid in the chamber. I like the description of a "wettish" vape though. that's exactly what it is.
When you say you're getting liquid in the mouth piece, are you getting the vapor settling inside the drip tip from normal operations or is it like you're drinking the liquid? Liquid will settle in the drip tip, that's nothing to be worried about, but if you're having flooding you have a different issue.
Everything needs to be sealed correctly and snug, make sure you put the orings on the clear middle tank section if you're using it. If the draw is tight and you pull hard when you inhale you can pull too much liquid into the chamber, adjust the airflow accordingly. When you fill, fill slowly and leave space for negative pressure so a good vacuum is created. If you flood when you fill, hold the KFL upside down and blow through the driptip while catching liquid with a paper towel out of the air holes, this usually clears the flood.