robw is correct,
Try to use water that is as pure as possible, so it will not leave deposits of minerals, like calcium behind. If you go somewhere like the VitamineShoppe, they may have some, but a health food store is the best place to look.
The amounts you are useing is so small, it wont really make a Big deal, your atomizer will wear out before you get much in the way of deposits. If you use well water, or it comes out brown, well then you may have a problem
Alcohol is ok too, but in small amounts. I would recommend clear, like vodka, or Everclear. NO LIQUORS or funky flavors, it will gum up the works totally.
The higher the proof the better. I would recommend 180proof or better. 151 should work fine too.
Limit the amount you mix in for 2 reasons,
One - Like water, over doing it will thin it Way out, PG and VG are oils, and alcohol breaks up oils. Water will mix, because VG and PG bond to water. It is used as a skin moisturizer.
Two - Alcohol will over heat the atomizer if used in large doses. It burns faster/hotter at a lower temp then the
juice.
10-20% would be ok, like water. If you use water AND alcohol, remember its not 20% one and 20% the other, thats to much

As always, Shake your mix well before Useing
