My guess, and this is only a guess, is that accuracy would be very poor. A RB only contacts the bore near the "equator", so the patch does a good job of supporting it. Additionally, the rifling is very slow.
A maxi, on the other hand, contacts the bore for .5"-.75" give or take. A patch would not support the bullet along its entire length, allowing it to likely tilt in the bore. Additionally, the rifling is more agressive and the patch might not grip the bullet enough to spin it, or might not hold up to the increased angular force created by the more aggressive rifling.
A sabot has petals to support the bullet uniformly for its whole length. Without this, I don't see accuracy being good.
Go ahead and prove me wrong though