I use around 1/2 to 3/4 cups of sugar for 14 cups of tea (14 cups + 2 cups of starter equals a gallon). I've been using different types of white tea, makes it's own type of tasty. Suppose to be really good for you too, high in antioxidants. I'm in California bay area winter time, so I use a heating pad and brew for about 7 to 8 days, or until I think it's at it's peak (I start sampling it at 7 days). When it's ready I bottle the batch for a second sage fermentation. Lately I've been adding to every bottle a 1/4 teaspoon of grated ginger that I keep frozen. Grating frozen ginger makes a really nice shaved gingery paste. I'll sometimes add drops of honey as well. Both the ginger and the honey help make a pleasantly fizzy drink after 2 to 3 days of bottling. Too much and you'll mess yourself and your kitchen. I've also used strawberries, and pineapple for very delicious results. I plan to use elderberry in my next batch, maybe with blueberries!
I agree with Halfdrunkhero, I like making my brew slightly more on the vinegary side and then adding the "icing" so to speak.
Rawvegangirl, it's nice to know there are Kombucha brewing vegans outside of this hippie town I live in. Happy brewing.