I've got 100mg/ml it was from e-liquid mart. I keep it in a cabinet.
Put 24ml of the 100mg nic with 76mls of vg and or pg to get a solution of 24mg of 100 ml.
Then to make say 100ml juice at 6mg use 25ml of the 24mg nic and 75mls of vg/pg/flavourings.
Divide the 24mg by a number that gives you the end nic% you want then divide the amount of juice you want to make by that same number and thats the amount of the 24nic you use.
24/4 = 6 so 100/4 = 25 ,,, 25 ml of 24mg in 100ml to get 6mg.
Ive vaped 6mg with 15% flavour many times and no harsh taste from the nic. Currently Im at 5.3mg.
Get nic from myfreedomsmokes , couple of other places people mention that they say have been ok.