I went by the book but the total amount was determined by what half a lime gave into the measuring glass, which happily was more than 15 mL. So I adjusted the remaining ingredients accordingly. Ended up with a Friday night helping, of what I believe is one of the best cocktails I have had at home. The generous amount of Angostura has its good reason. Because of the Grenadine I held back with the sugar syrup just a tad, turned out perfect. Absolute killer.