I have the family books for most of the peninsula known as Danischer Wohld between Echernfoerde and Kiel. It became part of Prussia in 1864. There were three parishes there, and the books have been filmed for two of them.
I would be willing to search for anyone with an ancestor there. I have Bahr ancestors, so maybe I'd be helping a cousin. I found a cousin in another line that way. Our common ancestor lived in the 1600s!