I've been experimenting with making my own shisha lately (I'm new-ish to the hookah, been smoking for a few months, but I like to make my own things when I can). So far my recipe has been 3 tablespoons tobacco, 2 tablespoons of flavoring (I'm using extracts), 2 1/2 tablespoons glycerin, 2 1/2 tablespoons honey. I've gotten great results so far, I've found that letting it sit for at least an hour before smoking it helps, if not overnight to let it soak.
I always use an organic tobacco with no additives and wash it to (boil in a pot of water for about 5 minutes, drain and rinse until the water coming through is pretty much clear). After its dry I'll add in the other ingredients. From this basic formula though I've always had to add more based off of the first smoke, sometimes its a bit rough and needs a bit more honey, sometimes the clouds aren't that thick, more glycerin, etc.
Only two flavors I've done so far have been orange and lemon, and comparing them to fantasia's line of products (its the only thing readily available in stores here, plus I like it for a few of its bold flavors) it has been even better than them. smokes a lot smoother from the washed tobacco, and tastes a lot better.