It wasn't until about the time of the Civil War, that they made many different sizes of powder. Afterwards there was a plethora of powder sizes for different uses, the powder for cartridges was different than that intended for shotguns, and muzzleloaders used a bit different powder than the rifles..
So what we have today for translation is 4f for the pan, and the 1,2,or 3f for the main charge.. When working with the National Park Service in the 80's to test drive their living history programs we couldn't have any powder in possession other than Govt issued.. All they had was 1f, it is surpising how well those hunks of miniature coal did work in the pan, but it wasn't as fast as 4 f, and as a result accuracy suffered some.