The online PocketShip Forum is hosted by Chesapeake Light Craft, and is an excellent source of advice, information and inspiration.
A builder posted a question about the rudder blocking in August 2019. He could not figure out what was what.
John Harris (PocketShip's designer) replied the following day with the answer. The blocking patterns in the kit had been incorrect since 2009!
He posted an invaluable diagram showing what the blocking patterns should look like. This is it.
Blocking is required for the front, bottom and rear edges, and for the cheeks and the top of the rudder.
The pattern for the front edge was missing, and the pattern for the bottom edge was duplicated.
The corrective posting gave all the information needed to fix this, shown in full here.
I knew that I would have the same problem so I printed the posting and filed it in my build manual, so I would know what to do when I got to that point.
So I made the missing pattern and laid them out to see how things fit together. Here they are on the bench.
It all makes sense now! Next step is to make the blocking pieces.