I think the bigger issue is not where the powder is in the pan, but how much! IMHO as a hunting weapon, a flintlock should never be carried in the field with powder in the pan. I'm different, what I do is push a toothpick in the touchole, lower the frizzen, and then hold the frizzen down and break off the toothpick flush with the pan/frizzen, then I load my main charge in the rifle. I do not take the toothpick out of the touch hole until I need to shoot it!, it's very easy and quiet to flip up the frizzen and remove the toothpick and add powder while I'm close to any animal. I carry a very small horn powder flask in my pocket with a wooden plug, it's
quick, quiet, and sure. If by chance I did not take the shot, I empty my powder from the pan and replace the toothpick either with the same one or a new one.
I do this because I do not want a fuse between my pan and powder charge, by loading my main charge with the toothpick in place and keeping it their I achieve this. By leaving powder in your pan all day it seems like it would pack in your touch hole. It seems to me keeping powder in the pan while hunting adds to many variables.
I also feel that my lock time is slightly better by using a toothpick during loading, I know the old timers used shafts of feathers to do the same thing, I have left guns loaded over a year and they always go off just like you loaded them fresh.