If you are not concerned with your horse walking off, what is the reason behind leaving theh alter on to get the bridle on? I personally throw the reins over his head, remove he halter, keep my arm under his jaw, and around his nose, grab the bridle and bridle him. Same when taking off the bridle. Leave the reins around his neck for control, take off bridle, put halter on, and then remove reins. It keeps you in control if he were to spook but I don't see any good reason to leave a halter on.