I agree that Tom Cunliffe's book covers the topic very well. I always felt that the shape of Ronnberg's pilot yawl didn't seem right to me. There are several photos of them in Cunliffe's book. If I recall correctly, there are also some small plans for them in the book. They are interesting boats.
When I built my model of the Mary Taylor based roughly on BlueJacket's plans, I scratch built the pilot yawls. It wasn't difficult. If I recall correctly, I just use the plans in Cunliffe's book. Here are some pics...