I'd look at him with someone else holding him. If he is standing on all four squarely and will stand there, that is 90%. If he is aired up and flags, my advice would be: "Don't change a thing."
It is hard for the judges to judge confirmation if he does not stand still. As for parking out, just remember that when you ask him to move his front legs, you are asking him to move. So you may lose the "standing still" that he knows. The rules actually provide that you can be asked to stand the horse on all four legs, not stretched, so the judges can see the horse's "true" conformation. (Never seen it done, however.) Horses tend to put their legs under them where they are most comfortable standing, so that's another reason not to mess with him too much.
Having said all that, I agree with the post above. Standing him on an incline (30 to 40 degrees is good). Let him get comfortable and quiet and then gently (WITH SOFT SHOES) lift his ankle forward. If he resists too much, I'd leave him alone. If he stretches out, at first his front legs will be in front of him, but after a few seconds, he will naturally shift his weight so they are perpendicular to the ground. If you do this for about a week, he'll do the same (more or less) on level ground.
I know I sometimes have a different view of the world, but a yearling that stands still and airs up and looks (by being left alone) is much better than one who fidgets, the handler jerks on him, and then spends 10 to 15 seconds trying to get him to park out. Just about that time the judges have spent all the time they are going to and you haven't let them see how nice your colt is. Just my view.