Thanks for the information on the Diamond Crystal Kosher salt.
It seems to me that there are essentially three ways for the average home pizza maker to determine conversion data for items like salt: 1) actually weigh a specified volume of the item, such as a teaspoon, on an accurate scale, 2) use the information provided by sources like nutritiondata.com and usda.gov, and 3) rely on the information provided on the label. Of the three, item 3 seems the least reliable, in part because of rounding factors. A good example of the latter is the data given on bottles of oil. I checked over two dozen different bottles of oil at the supermarket the other day and they all said that 1 tablespoon was 14 grams. It didn't matter what the oil was. There were all the same. In the case of oil, I found the nutritiondata and us.gov sites to provide more accurate data.
This morning I took several weighings of my Morton's coarse Kosher salt, using a MyWeigh digital scale accurate to 0.1 gram, and the average was 5.59 grams for a teaspoon. The box says that 1/4 teaspoon is 1.2 grams, which is 4.8 grams when multiplied by 4. I leveled the teaspoons with the flat back edge of a knife. So, it was not "scant" or "rounded" teaspoons that I used. It occurred to me that since salt is hygroscopic, and since I keep my salt in a kitchen cabinet at room temperature, the salt may have taken on some moisture which might have affected the weights on my scale. In someone else's kitchen, the results could be different.
By nature, I try to achieve accuracy and precision in what I do, and in using conversion data for the Lehmann and other dough calculating tools, I would rather have accurate and precise data than estimates. So, of the three choices mentioned above, which is the one that you deem to be the best way of achieving accurate and precise data? I realize that the average person doesn't pay much attention to how an ingredient is measured using measuring spoons. They just give it their best shot. Also, Morton's doesn't seem to deter anyone from using their Kosher salt as they would their usual table salt.
I might add that when I checked the nutritiondata and usda.gov websites I could find only data on table salt, not Kosher salt.
Edit: Corrected scale accuracy to 0.1 gram.