Nice!!! I love Tibicos, and I enjoy reading about how others have experimented with it. I never liked the citrusy water kefir, at least the few times I tried, even though the fruit was always peeled.
My favorite flavors are ginger (very classic), cranberries, and fresh basil leaves. But I've tried it using a huge range of fruits, herbs, roots, and flowers. Elderflowers are delicious!!! Rose petals don't have a strong taste, but the smell is divine. Beet root has an interesting taste. I like it, but not everyone agrees. Mint is something I don't like, but when I used to sell water kefir at the market, it was highly popular.
For minerals I use piloncillo. Since I don't always want its flavor to interfere with the taste of my drink, I tend to alternate between one batch for me, using sugar and something for flavor, and one for the cultures, with only piloncillo, which I then pour down the drain.
As for the water, I use simple tap water, after setting it out in the sun for a few minutes to let the chlorine evaporate. I'm actually trying to get all those lovely germs from the infamous Mexico City water pipes into my Tibicos. If the culture rejects the new bacteria, they kill them off. If they accept them in the community, they keep them under control, so they won't reproduce to where they can get you sick. However, by ingesting them, your body will get to know them, just in case you are exposed to them at some later point.