What kind of shoes do you have on him?
His style is much like Selena's... And both of them are naturally front-endy, I'm wondering if a different shoeing situation would help him as much as it helped her.
Butttt that's not what I was going to say originally, lol.
He's not really making any effort here. He's just cruising. That's fine for now, but that's just something to keep in mind that you might start adding a little pressure into those turns to make him snap. If he doesn't snap and fire out of it, give him a good kick. Just one kick, nothing crazy, to say "Yo, buddy, seriously. Let's go." Then relax again. I do think he is dropping a little but that's from lack of effort. It's not so much he's throwing himself onto the barrel, so much as he's saying "Ehh...God forbid I burn another calorie lifting my front end..."
On that first barrel as soon as he blew wide I would kick hard with the outside leg and make him turn/spin a full 360 if not more, as long as the shoulder moves. He's not lifting and he's bowing up on you, which is why he is coming off wide. Can he do rollbacks along the fence and spins?
Another thing is I would not wait so long to get his lead changed...In practice, if he doesn't have it by halfway flying, then go to the trot and change it. In competition you may not get it until a stride or so before, but in practice you wanna get it down pat halfway.
I mean, he's come a long way and he's going well. Those are just the little tweaks I would make to him.