On the topic of the propeller/aperture/and rudder-stops, all guesses were right on. The prop is larger because the engine (a Yanmar 12 hp) turns a lot slower than the original engine. The larger aperture was obviously necessary to accomodate that, and the rudder stops were necessary as well.

Tomorrow, Friday September 7, Kestrel is to be launched. The bottom is painted and the interior re-varnished, and she is due to be splashed in the afternoon. I'm going down to take pictures and will post them.