I have never heard of vanilla stevia. Not sure if it is available in Australia as yet. I use stevia all the time, especially in ACV drink, but I didn't like it with the green drink. It just made a yucky drink taste sweet and yucky.
I also tried lemon and I think if I were to drink that too often it would put me off lemon juice. I think the best thing is just to keep drinking it and get used to the taste. It gets a little easier to drink each time. And I think just knowing how much better it makes me feel makes it so much easier to get down.
Vanilla stevia sure is an interesting concept though. I would like to try that.