I'm glad you're going to work on it. My suggestion is work on it only a couple times per day. You're can't stop it cold turkey and trying to do so is usually a recipe for failure. Work on it a few times a day and you will building change the habit. Also, I hope you know you don't have to lower your head. Lowering your head is something you picked up, just like the bridge words. You feel you need to do it to move past stutters, but you can move through stutters without it.