First, thanks for your efforts with the videos. I think they are great, good quality, and if you click to full screen, and watch close, I am surprised at how well you an see the action.. I know its not an easy task to get a good vid..
So many methods, and different ways to run dog.
I know, if it were my training day, I would have been chastised as to how I originally lined the dog to start with. You had Rowdys spine lined to the left,towards memory bird (M1) right off the bat.
I have been taught to always line the dog spine to the go bird (M2 in your vid), then step way up on the dog(he isnt allowed to move his buty or feet,just his head) to get him to look to M1. When he is keyed on that mark, throw it, but do not be in such a hurry to then step back, or away from dogs shoulder, to pull him to M2. make sure to take your time,and reaaly let him have a chance to stay focused on the memory bird, before you pull him to throw go bird.
This method has really helped me with unnecessary movement by the dog, and has improved my "sit" at the line.
I think you have a wonderful dog in Rowdy! I bet you will go far with him..