Butterfrog help requested

After resisting my coach's suggestion to learn butterfrog, I am finally relenting and taking the advice of King Frog, Nadine Day, and my team's relay coach, Donna Hooe. I can swim a legal butterfly forever (well, 2,000 yards non-stop that I know of), but it's slow. I would like to improve my times on both 200 fly and 400 IM, so my goal is to learn a legal (and good!) butterfrog. I saw instant positive improvements in my stroke count and 200-pace, 25-yard split. What used to be a 10-stroke 25 yard butterfly is now 8 strokes, and my time at 200 pace dropped almost two seconds. I have only practiced this for a few hundred yards, so I have a long way to go to getting it right! First of all, the undulation is missing, and I need to get the feel for it. I also notice that I'm not getting completely around on recovery and my wrists are bending on entry. In time, I'm sure I can work these out. Is this butterfrog legal? What suggestions do you have on how to improve? King Frog, I would especially appreciate your feedback as always! :agree: Topside- http://youtu.be/0yVfdN5CcXY Thanks flyers and frogs!