Try using straight glycerin (glycerine, glycerol) in you
juice mixes with the flavors.
I have some Ruyan 36mg/ml
juice called Flue-Cured Tobacco. I cut the
juice with 50% 36mg juice and 50% straight glycerine. Wow!! Major vapor. I am not saying you should consider using a nic liquid, but the glyercine really produced tons of vapor. As with any non-nic additive, glycerine will decrease flavor so you will have to experiement a bit to find your perfect smoking fluid.