I am relatively new to blackpowder as well. I also have an optima. After trying several methods of cleaning, I have narrowed it to the following:

pull the breech plug and soak it in cva solvent. while that is soaking, I now use butches bore shine for blackpowder. saturate 3 to 4 patches run them down the barrel several times eachthen dry patch it several times. Once its good and dry, I use couple of patches of birchwood casey lubricant and the barrel is done. Cleanup breech plug from soaker and it done. I also use the birchwood casey around the action and hammer. Spray it down in there and you will be amazed what junk comes out of that area. Wipe the excess and your good to go. By the way, I wipe the exterior down with a hoppes silicone rag before storing.

Not sure if your optima is nickel, if so, wipe whatever cleaning solvent off immediately or it might stain the finish.