Are there calculators for batching down a drink nito single servings? (x-post from r/bartenders)

I want to do this:4 cups Honey Smacks cereal1 gallon whole milk2½ bottles Rebel Yell bourbon2 oz. vanilla extract1 quart simple syrupNutmeg, for garnish...but this is terribly expensive to try if I don't like it enough to drink it all! I need to batch it down into 2 or 3 servings so that my co-workers and I can try it out.Are there any calculators online that I can plug this stuff into that will convert it to 2 or 3 servings?