Well, since that time I have yet to be able to find that 20 x (fold) vanilla oil. Now this typically would be contrary to vaping logic and warning, however the fact is that the process by which the vanilla oil is extracted plus the big deciding factor on this is that vanilla oil is not quite the same as 98% of other oils as those are typically steam distilled and carry many other well, for simplicities sake just called them alcohols, not really what most people think, anyway, Vanilla oil is an immiscible oil, meaning that it will not mix with other oils, however the good thing about this the fact that it will leave behind the aroma and flavor without all the added alcohols etc. But for vaping purposes, the actual pods and beans can be suspended in a PG solution, you can of course use the PGA but you shouldn't require all that much to assist in the extraction of the flavor and aroma and what I have done when I first started to experiment with it was use a small amount roughly 10% PGA in relation to the amount of PG, now as you are already aware and have stated this can take months, but after that time period which I am assuming you are shaking it as often as you can and keeping it in a dark cool place, when you feel it's close to being done and want to test it, with all the mixing you do I would assume you may have a beaker, what I would do is to put the mixture after straining if it's ready into the beaker and cover it with a filter to keep things out but still allow for evaporation, you can also heat it but you have to be very careful here, I never let mine go over 140 degree's, allow it to sit after the heating if you choose to do that optional step, which helps remove some of the PGA and the let as much of the rest dissipate, this will not remove all of the alcohol even with heating some amount will remain, that's just the nature of it, and after a few days it should be good to go.
There are so many people that think you can remove all the alcohol out of a liquid by heating, this is also mentioned to chef's as well, if you watch cooking shows they will tell you that this or that sauce when heat or flambeed will get rid of all the alcohol, this is not true, it will remove some, I have a chart in my files somewhere I will have to search for it, haven't used it in a long time.
Anyway, this got a hell of a lot longer than I indented, sorry about that.