I have a friend who makes gourmet chocolates. She gave me 9 bottles of concentrated liquid flavorings. (Way too many that I could possible use) I would like to make a couple of test cakes and incorporate some of the flavors. If I make a 9" cake should I use only a teaspoon of flavor? I would like it to have a hint of flavor and not over power. Any suggestions? Also, if it does not work out I don't want to waste them. What should I do with them?