How many grams of powder are used to make a single double? Theory of powder loading

How many grams of powder are used to make a single double?

I can tell you how many grams of powder I use, but that's for my beans, my grinder, my powder thickness, my powder strength, these links are closely linked and can have a direct impact, when you change one of them, the rest have to be changed. In principle, we install more coarse powder and less fine powder, of course, you can fix what you think is the ideal amount of powder, because the powder quantity and scale are relatively controllable (compare the numerical value, the scale is how much, the amount of powder is a few grams), for example, I am used to using 9g for a single serving and 16g for a double.