I used 4 drops of essential orange oil in a gh1 menthol 10ml and it was delicious, but i wouldn't reccomend it as it made me feel stoned and seemed to aggitate my upper respitory tract. tho the relaxed feeling is why orange eo is used in aromatheraapy, and it was a nice calm feelig not a scary one.
Tho those oils are so strong i could've put 1 drop in and still would've got the flavor still.
Now eos are used in aromatherpay and are inhaled in water steam or actual vaporisers. But the volume of liquid they put 2 or 3 drops in is a lot more than the 1.2ml that say a tank cart can hold and they do not directly inhale them like us vapers do... A lot of these oils are surfacants, meaning they strip layers of grease etc from surfaces....
I did put one tiny drop of spearment eo into 1ml tank cart that already had some menthol in and that was okay and tasted fab, i mean these oils do taste tremeandous, but we just don't know the risks involved without in vito studies, so not worth the risk imho.
Using them perhaps in the mix ratios per volume of liquid that aromatherapists use might be okay, but then in aromatherapy you are not vaping them all day long, every day....