You'll see little difference in POI...I sometimes use Pyrodex R-S in my inline when WalMart sells it for 7-10 bucks a pound...I use the same charge with Goex, but I use FFF because I use this for my flinters...

My inline load is 80grs FFF Goex and a .430 Hornady XTP inside a Harvester sabot...

My round ball load for my .54 is also 80grs FFF Goex...