RBs work fine. You can't overstabilize a RB. Go ahead and shoot them. You may find that accuracy requires you to use a pretty tight ball and patch combination, and your rifle may be a little fussy about the powder charge used for consistent hits, but it will shoot RBs just fine. Usually, you will find accuracy with a RB in a fast twist by keeping the powder charge in the modest ranges for that caliber. If you want to load the gun for hunting, try using a filler( corn meal works well, is cheap, and available in most houses) or OP wad to seal gases behind the PRB and protect the patch from burning from a heavy powder charge. Barrel harmonics of YOUR barrel control how much accuracy you will get with heavy loads behind a PRB. Use a chronograph to work up loads. When you find a powder and PRB combination that give consistent velocity readings, it will also be the most accurate. Use FFFg in your percussion gun, compact the powder, but don't distort the soft LEAD Ball by pressing on it or banging your ramrod down on it. If you hold the barrel vertical when you pour in the powder, the drop of the powder to the breech will compact it better than all the pressing you can do on your RR. Compacted FFFg powder give more consistent velocities than loose powder, in a percussion gun.
Competition shooters use a drop tube that is inserted in the barrel to allow the powder to drop all the way down the barrel to the breech, so it does not cling to the sides of the barrel as it drops. Using a drop tube allows them to load a barrel that has wet oil, or lube, or even residue in it, without fouling the powder charge.