First I just want to say that wide hands actually aren't a bad thing when used effectively, like if you're using them to support your horse through turns and corners, or when approaching a jump. They can also be extremely helpful when riding young horses who have not yet fully developed their muscles & found their balance, or when riding any horse who has a tendency to stumble a lot.
For starters, you need to put more bend in your elbow and lift your hands. You never want to be resting your hands on your horse's neck or on your saddle. (The only exception to this would be reaching forward and grabbing mane if you feel yourself losing your balance, as breaking position is always preferable to ending up on the ground.)
I noticed that when you turn your horse, you tend to bring your inside hand way out and back. You should be turning your horse with your eyes, inside leg, and outside hand. The outside hand should have a consistant yet elastic feel on the rein, and act as both a support and a block - the support will help to keep your horse balanced through turns and corners, but it'll also serve to block him from veering away from the direction you want him to be going in. Your eyes and inside leg should work simultanously through turns. As you turn your head to look where you want him to go, your inside leg should apply pressure just behind the girth to push his back end out into your outside hand, allowing him to make a nice turn. Always looking ahead towards the next turn or obstacle (or towards the center, when making a circle) will help your horse anticipate where you want him to go, since by turning your head you also are making very subtle movements with your seat as well that your horse will pick up on (even though you probably won't even notice that you're doing it.) The only time you should really have to use your inside rein for turns is for corrections, such as when he ignores (or is unable to understand) your seat and leg, or becomes crooked. A simple squeeze with your fingers in a take-give motion on the inside rein is best, and this would be made easier for you if you shortened your reins a bit, since it would eliminate the need for you to pull your hand so far back (since essentially your hands should be staying even with one another).
He's a very lovely boy :)