Here's the problem: the math is one thing, but the absorption of the nicotine is another. You get a LOT more nicotine absorption with cigarettes due to the fact that the tobacco companies add chemicals (ammonia usually) to increase the PH of the smoke. That gets the nicotine into your blood stream quicker and more efficiently. Additionally, the NZ study strongly suggests that nicotine in vapor is not absorbed through the lungs at all, but enters the body through the mucous membranes in the mouth, throat and sinuses. Further, the amount of nicotine absorbed through those avenues is something on the order of 1 tenth of the amount you get with analogues through the lungs. So, even if you come up with a 1:1 relationship between the amount of nicotine in an analogue and the amount in a certain number of drops, you're still fighting against the basic body chemistry of nicotine absorption. The general consensus seems to be that it takes about 10 drags on a PV loaded with 18mg fluid to match one drag on a standard analogue. Opinions very though. Some people use 36mg fluid and say they don't feel any nicotine effects at all. Others use 11mg fluid and report the early stages of nicotine poisoning. Everyone's chemistry is different, so the numbers don't really tell the whole story. The best way to go is to experiment and find a combination that works the best for you personally.