How much powder you put in the pan depends upon how the gun is setup...I have 2 custom made flinters and the touch hole is covered by the frizzen when it is closed, so I can put a full pan of powder in them without the fuse effect...This is the proper position for a touch hole, high and centered over the pan...
When casual shooting or squirrel hunting with my .40, I don't pick, no need to, the gasses from the previous shot come out of the touch hole so it cleans during the shot...When shooting in competition and hunting, I load into a clean barrel and the touch hole is also clean...
Now, I use Goex FFF in both my .40 and my .54 and charges in the .40 are 25 grs and 80 in the .54...If you use higher charges of FF then you might have more residue left after the shot, so picking might be necessary...I'd suggest trying both ways (picking and various pan charges) to see what your gun prefers...Good Luck
btw...I have noticed on other boards that Elephant usually doesn't yield the same velocities as Goex...It seems that Goex is stronger and burns cleaner, so your results might vary...