Ummm when you are backin try to look just infront of you or even at the top of your horses head the reason for this is when you look down your body weight shifts the slightest bit and that can affect the horse when backing.
Try and sit deep in the saddle and lean back a bit, have you feet move ford enough for your to feel what you are asking when backing.
You need to get you horse to understand when you are askin him of this it means back and soon enough you will have him on a loose rein and beable to do that with him understanding, so then he will look more westurn with his head set in the correct place as I explained to you last time.
But yeh just try and stay of the bit with a loose rain but apply the things above and then once he understands then start on loosning you reins.
Hope this helps for you