I agree with the over shot card options, but I must question the use of toilet paper as an over-powder wad. I don't see it being very good for patterns due to a lack of cushioning. There are over-powder wads available that are better choices for pattern control. The choke is only part of the formula for good patterns. There have also been shot cups offered that were sized for use i muzzle loaders, but I have't seen them lately. "Circle Fly" brand vegetable fiber wads are designed for use as over powder wads.
Good luck
Keith