Thomas Keller says in his cookbook ad hoc at home that he usually uses Diamond Kosher Salt. The density of Diamond Kosher salt is different than the density of other brands of salt. Here are some approximations for converting recipes by Thomas Keller.
Diamond Kosher Salt, 1 tablespoon = 12 grams
Morton Kosher Salt, 1 tablespoon = 16 grams, 75%, 3/4
Baleine Sea Salt, 1 tablespoon = 18 grams, 66.7%, 2/3
Table Salt, 1 tablespoon = 20 grams, 60%, 3/5
According to these values, a person using a recipe from ad hoc at home should use 3/4 an amount of Morton Kosher Salt, or a little more than 1/2 an amount of sea salt or table salt. 3/4 tablespoon is equal to 2 1/4 teaspoons. My notes on salt are in my blog post Various Tips (Wisdom) For The Kitchen.