My question: If I grant a duchy to a vassal for which I hold all the county titles, then he gets basically no benefit out of it, correct? I.e., I'm obviously not his vassal, and the lower titles beneath the count title (mayorships, bishoprics, etc.) are my vassals, not his. Is this a good way to get rid of a duchy title and avoid holding too many? I realize they get opinion penalties because they desire the counties, but if you can manage that is there any downside, or is better somehow for me to hold the duchy title over the counties I hold?