I shot Blackpowder Cartridge Silhouette for years, and have shot muzzleloaders since I was a teen. All BP is not the same, and our different geographical areas make results different. Fouling will be different in the humid south vs the dry of desert regions. Different lubes will react differently, as will how tight the load was, and how much powder (too much/too little).
I shot the old, grey, irregular grained Elephant, the "improved Elephant" that was black, shiny and much more consistent in grain size, Diamondback (improved Elephant after the plant was moved) Goex, Kik, and Swiss. Elephant ignited, made smoke, lots of soft grey fouling and modest velocity. "Improved Elephant" and Diamondback made less fouling and more velocity, first lot of Kik circa 2000 had soft grains, and worked fine in frontstuffers, but a bit erratic in cartridges, Goex varied from lot to lot and variety (ffg vs Ctg) and Swiss.....made the most velocity and barrel heat, so also hard, dry fouling. BPCRS shooters liked the velocity of Swiss, but resorted to wiping the bore between shots to control fouling and heat. Those of us who shot prior to the introduction of Swiss (first imported by Goex after their 1996 plant explosion) almost always used a blowtube between shots to minimize movement in position, and introduce moisture and cooling to the bore. Combined with a good lube, this worked well for lots of folks.
I started with roundball guns and Goex, so learned to deal with fouling from that perspective. I found that when shooting Elephant and Diamondback that a kicker charge (38Spl case) of Goex fffg under the primary charge solved fouling issues. I used Swiss fffg in a cap-n-ball revolver and it worked fine there.
I've never found found Schuetzen for sale locally when I was in need, so no experience there.