The blue halter looks nice (color) on him, but it is a tad to big, but don't worry about it. It fits better than the show halter. I sent the yearling halter out today, via USPS, so you will probably get it on Tuesday next week.
The halter should fit snuggly. The straps that go under the throat latch should be fitted right up against his throat and under his cheeks. The nose band should fit right up against his cheek bones and be fitted against his muzzle/nose. The pole strap should be snug. You'll feel like you are choking out your horse and you've fitted him with a muzzle. When the halter gets there see it it fits and if you need help with it's fit, take some pics and post them. This is how a Quarterhorse Judge, ex Champion Halter participant, should me how to do my horses halter.
Good luck this weekend. And as my trainer is always telling me, SMILE and BREATHE!!!