Skip the Oxens. They are overall less "reliable" in use without serious maintenance. Also, when they fail, they tend to fail cleated. Talk about real interesting in a stiff breeze...

The original 6.0 did have a smaller self-tacking jib. Was a really nice boat. Too bad it didn't catch on.

Take a look at any one of the modern self-tacking jib boats and see what you would have to add in addition to the new jib to go to a self tacking setup. Looking at a couple of F18s and Nacra 20s will show you what you need. Take time to look at the relationship between the clew of the jib and the sheeting angle (up and down, not side to side) to understand how your new jib will have to be cut.