I stock 2F, 3F, and a single can of 4F (for flintlock priming only). It seems to me that some shooters like to keep it simple, and stock only one powder for most purposes. If it were me, I'd likely settle on "CARTRIDGE", but 2F will do most any job. It is safe to go slower (fewer F's) but loading faster powders than required can raise the pressures faster than muzzle velocity.