I find that, with single shot rifles, chamber fouling with "clinkers" often occurs with large grain sizes. I shoot 45-70, 45-75, 45-90 all with 3F and find that smaller grain powder is cleaner than large. Have experimented with 2F but found chamber fouling was a big issue with the larger size BP. The large grains got stuck in the chamber and will not allow chambering more rounds until wiped out.
I also find that all BP makers I have used offer almost identical performance. Swiss, Goex, Old Eynsford, and Schuetzen all seem to offer the same results, so whatever is available is what I use. It is a very simple compound, with 75% Potassium Nitrate, 15% Charcoal, and 10% Sulfur so cannot see that there would be much difference between brands though it remains personal preference for some.
I use the rule that many muzzleloaders have espoused forever. Anything 50 caliber and over use 2F and anything under 50 use 3F. Most BP Cartridge guns are under 50 caliber, so 3F seems to be the best choice in my mind.