I'm doing just this tomorrow, taking my .69 Musket out with a variety of paper types, a bunch of round balls, .660 slugs and different lubes and I'm just gonna go to the pistol pits at my range and shoot .
Sounds like good times. I test fairly often looking for better loads for my guns. The load and lube used in the Scout project was the result of one experiment. I found I could shoot over 50 rounds straight with no issue with that combo. Since we aren't allowed to paper patch in the NSSA, that's one avenue I have yet to explore.