I enjoy this recipe, but feel that the grapefruit juice needs to be more prominent. If you use 60 ml white rum, 7.5 ml Luxardo Maraschino Liqueur, 22.5 ml grapefruit juice, 15 ml lime juice and 7.5 ml rich sugar syrup (2:1 syrup), you get an excellent Hemmingway daiquiri. Add a shake of Absinthe to make an interesting variation; The Sun Also Rises.