Below post #59 from
flavourart - Page 2 - E-Cigarette Forum
I test in straight PG so no biggie. For example 9 drops PG 1 drop flavour = 10% flavour.
If that was not enough I do 8 drops PG 2 drop flavour = 20% flavour (different mix)
If 20% was too much, then was it closer to 10 or 20. For argument sake here let's say it was in between. Mix both bottle together and you have 15% flavouring.
On tobacco, they are touchy, do as I explained and work from there.
For flavouring juices, most of the time we start at 10% some folks start at 5% which would be 19/1. I find 5% a waste of time. The tricky part is when refining the recipe. Like 5 drops/10ml of marshmallow in my Cuban Cherry to take away the dryness. This was a educated guess from 1 drop/3ml, it didn't need 3 drops, it needed 5 drops which was 1 drop/2ml.
My PT is always fitted with my pen adapter a fresh atty that I am using in developing that liquid. Which I turn to a couple of times a day, over the course of several days because recipes mature over a couple days then plateau. Once I am happy, I make a 10ml batch. keeping notes. If there is something I want to try, I'll syringe 5ml into another bottle, and keep notes. This doesn't happen too often though. I use 5 mls, because that is easily dbled into 10, 20 or even 30ml. The caveat...
OK so let's say I found a juice that required 1 drop of X in 5 mls, it also means that would equate to 2 in 10mls, or 6 in 30mls, not all the time. Some flavours will tune out others in larger quantities, especially some of the strong ones. Sometimes I find that although the ratio called for 6, a more accurate count would be 5. These are the special notes that need to be kept dilligently. My RY5 is a prime candidate for the latter discussion.
I was a premium cigar smoker and as we know the majority had/have very complex flavours, same thing goes with pipe tobacco. The nuances have to be finely tune, something all the calculators out there simply do not do, as they don't calculate a fraction of percentage or 1/2 or even 1/3 drop. Sooooo
In my recipe book I keep track of percentages, drops, size of recipe, PG/VG ratio, distilled water (more vapour) and fine tuning drops for larger recipe sizes etc... I like mixing 10mls at a time, it's a nice size and not too much to vape if you screwed up, which is nearly impossible if you took all the baby steps previously mentioned. but because of these 1/3 drops you may very well be forced to mix let's say 12 or even 15 mls.
Hope all this helps.