I dropped my HomeBrew juice about 2mg/ml. This is so I can do it all day, and still only get about 6mg of nic a day.
I tended to add a bit at night, but I found the MontyPython'sGrail of: 1 part Homebrew juice, 1 part PG, and 1 part PGA (Pure Grain Alcohol, or everclear 75%). This works better than any juice I made. This is what I was lacking at the end of the day, and have now found it. (I just will smell like a "still" if I did it at work.)