Thanks DuBois and Pat!  Nice to have so many experienced eyes looking over my bow.
This is my first buckthorn bow and I really like this wood.  It's lighter and softer than I would have guessed, but evidently very elastic.  This one weighs a hair over 16 oz.
I'll take beginner's luck on this one, Steve.  

  I think I quit on it 3 times.  Your long string tillering post and Gordon's build along dealing with that reflexed vine maple stave were a great help.  Gotta remember that for the next one, now.