1) For defensive purposes, use Buckshot. The slug eliminates the advantage of a shotgun. Your choice, between #1 and 00 Buck. Use the IC choke. Cylinder is best, but IC is Okay. You can TEST buck from the rifled choke... It may actually SPREAD the buckshot more, which at short range would be good.
2) For big game hunting... Get a slug-specific barrel. The rifled choke tube is a "novel concept", but I doubt impartsmuch stabilizing spin in what??? 3 inches?