One thing I'm noticing is that you are allowing him to go into his transitions strung out. The backing is helpful to get him underneath himself but the trick is to go straight into the transition from the rear. Meaning he is on his hind when you ask him to move forward. You end up allowing him to take a few steps before transitioning which ends up allowing him back onto his front.
You actually aren't doing all that bad. You are definitely headed in the right direction. Good luck!