Is the intent to add the chilled water to the glass, or the shaker? Currently it's missed out of the recipe as only the first 3 and the kirsch are mentioned.
When I use ice from the refrigerator ice maker is seems to melt faster than the ice I make for drinks, to get the cocktail chilled. I presume that using much harder (colder) ice would not reach the proper dilution. Unless you’re interested in shaking each drink for a few minutes each. At least that’s my best guess.
