I can't speak to how well such a formula will work, but I can say I'm also very interested in medicating my e-juices with things like caffeine and ephedrine (ie not nicotine) unlike the majority of this site.
There are various things I would try in your case:
1. Make a tea of sorts out of your ingredients and boil it down to what you think might be a good potency. The recipe you gave doesn't have any sort of water to herb ratio so I can't really ballpark an active concentration. But once it's boiled down add it to an appropriate amount of Vegetable glycerine (VG) and you're ready to vape! This method may destroy some of the good feels (actives) in the plant through heat degradation, but it takes far less time then method 2
1b). alternatively expose your herbs to isopropyl alcohol(IPA) for 24 hours in a warm, dark environment. Mason jar under the water heater always works for me. Then evaporate the alcohol (WITHOUT A FLAME PRESENT IN A WELL VENTILATED SPACE) to a good herbal concentration and add to VG. Because the IPA evaporates much more easily then water, you're far less likely to destroy actives. However the ipa may not pull all the actives from your plant, and who wants to leave all those good feels behind?!?
2) make a tincture with VG and propylene glycol(PG) directly by introducing ground herbs to VG/PG in a mason jar, then leaving in a warm dark place for a month or so. This is what people who make their own ........
e-liquid do, however it's rather time consuming and could lead to a product with low levels of active good feels. The tastes from all the herbs would seep into the juice and make an oh so tasty product so it may be worth it
I'm sorry I can't be more specific with volumes and such, I'm not familiar with many of these herbs. Make sure you get the Dwarf Skullcap, 8/10 good feels for such a cheap and legal herb
For the herbal sedative extract used with tincture method, I would suggest adding artificial flavour or some catnip to give it a nice taste. Valerian has always tasted nasty to me, I can't even drink a tea that contains it without recching. Happy Hunting, if you make an effort please report back because I'm very interested!
[EDIT] Forgot to say, you might want to filter out the plant material with a coffee filter or french press. From experience,
vaping juice with suspended bits of plant matter isn't pleasant. and filter before you boil everything down or you'll lose a lot to the filter
