Your fix idea sounds much like mine. If you ultimately take that route I'd wrap the inner tube around in a direction counter to the direction of the shaft rotation, that way it has a natural tendancy to "spin" the oil back toward the center and not let it collect in the overlap. My concern is getting the made up "boot" to taper properly so I don't get a bunched up end that I can't seal properly. The split boot may ultimately be better.