Here they are:
I used 3/4" red oak.
That's the best pictures I have of the new 'battery tray' and how I attached the ankle outside of the frame.
Here's one or two of the ankle during test fitting, showing some of how it's mounted to the frame:
That's pretty much what I have on it, hope that helps a little.
And maybe one of these days I get back to working on K9. There haven't been any updates, because I haven't done any work on him since probably August or September...