I was looking at an articulating rudder earlier this year to add to my Willard 36 displacement trawler which I am refitting. After many messages, I have decided on a fishtail modification of my existing rudder. I talked to several people and belive it will get 80% of the benefit with 20% of the cosfe/effort. Plus, not having a moving part below waterline is a good thing.
That said, if your heart is set on an articulating rudder, well, I tried the same folks on BC you note and did not receive info back. I also tried reaching pit to Dave Gerr, NA and author of Propellor Handbook. He wanted a consulting fee of course which was reasonable, but I ultimately decided to go a DIY route