Weighing your flour is the most accurate way to measure. If you aren't going to weigh it, make sure to spoon it into the cup, and then level it off. If you scoop the flour out with the measuring cup and then level, it could change the outcome of the final product.
This recipe was tested using Diamond Crystal coarse kosher salt. If you use Morton's kosher salt or fine salt decrease by about half for volume, or use the same amount by weight.
You can store it in the refrigerator for 2-4 days or the freezer for up to 3 months. If you plan to store it for an extended period of time than wrap it up twice!