Aha....so more questions. What is the resistance of the atty you're using? What is the pg/vg ratio of the juice you're using? What is the flavor of the juice you're using?
Vapor production:
In my experience, the 306 has been a fantastic vapor producing atty. However, the only time it hasn't been for me is when I have flooded it. Too much juice in the atty stops the coils from getting hot enough to produce vapor in the quantity you're looking for. So my first guesses are...
1) the atty needs to be lower resistance.
2) the juice needs more VG base.
3) your technique needs tweaking.
There may be other issues, but these are my top 3.
Throat hit:
So you're doing zero nic....that's a toughie. However, I know certain flavors produce more throat hit than others. So things like cinnamon, menthol, and tobacco flavors will hit harder. Keep in mind that most tobacco flavors will inherently have nic in them so that is out. I have also heard that you can add distilled water or PGA (a drop or 3) and that will increase TH, but does nothing for the flavor. Also, PG base will give you more TH than VG...but again, the VG is what produces more vapor.
I know there will be more answers...as there are much more knowledgeable folks in here who can offer you their wisdom. I sure hope you find something that helps.