I changed the title, please - everyone who reads this - name your thread in a clear way otherwise everyone has to see inside what it is about, of all the infinite possibilities. Good and mysterious from a marketing perspective, impractical and unwanted at boards - BL/PD also.
Anyway on with the actual topic: yes I agree with sekio. Depending on the solvent and surface tension drops vary in volume and they also vary for a single solvent. A while ago there was a thread posted about a suggestion how to go about making a preparation that allows you to dose a psychedelic by the drop.
If you know what you are doing, after unquestionable experience with basic chemistry, then for *some* compounds that have an acceptable therapeutic index (margin of safety) you could do this but still every drop should be a fraction of a dose and not a whole dose. So with 4 mg you got a part of it in the right direction. I am not sure what the statistical deviation is with aqueous or alcoholic drops of psychedelic solutions but really this is asking for problems. There is no true purpose either, people think it is cool because it resembles liquid acid (which has a large therapeutic index, almost without competition). But beyond that, it is just better to use volumetric measurement... that means you actually have to be able to accurately measure the volume of your liquid!
So the 'cool' argument is not enough from a HR perspective, I advise against it and beseech you to act responsibly.