Another clinic report, which I’ll put here because this is where it is most relevant.
Buck has a long list of where he wants his horse in a snaffle, before he goes into a bosal. From his description, it would be pretty much a horse doing 3rd level dressage, maybe Prelim cross country, or 3’6" working hunters/derbies.
Now, other people can, and will, do it differently. But Buck’s goal is to have a horse in the bridle that has as much lateral softness in him as ability to collect longitudinally. Lots of people take the lateral out of their horses when the get him in a bridle.
But Buck wants a horse 'In a soft Feel" (in other words, On the Bit and not behind the vertical or bracing against the reins–no crank or flash needed), walk, trot, canter, leg yield, shoulders in, half pass, haunches in, etc.
He wants counter canter, flying changes started, simple changes rock solid.
He wants a horse ridden outside a lot, and confident to go on a loose rein walk, trot, canter, gallop. He wants to be able to steer accurately with his legs, no reins (so he can guide his horse subtly with no hands when roping).
He wants to have roped/branded calves, and doctored cattle in the pasture. (Meaning, you rope the calf, tie off the rope instead of dally, get off the horse, and give the calf medicine.)
He wants to have worked stock (colts, or cattle in a feedlot, say) with a flag.
He wants the horse really gentle, so he’d not just be rideable by a novice or a kid, but take care and fill in for the kid- to babysit.
And once the horse progresses through the bosal, two-rein, and then into the bridle, he will go back to the snaffle if he ever needs to. If he were to take one of his bridle horses foxhunting (assuming the horse had never gone foxhunting), he’d go back to the snaffle so he didn’t get the horse in the mouth inadvertently. But his point was, his horses have so much lateral softness in them, so well built in, and he continues to ask the horse to bend laterally, so that if he ever goes back to the snaffle the horse is ‘just as he left him’ in the snaffle.
Buck says he rides a horse for at least a year and a half in a snaffle, steady, before he’s ready to put the hackamore on. He might start a colt at two, put 6 or 8 rides on, turn him back out. At three he’ll do a little more, maybe go out in the pasture to move a few cows, but not much more. So he won’t start riding steady until the horse is 4 or 5. So you won’t likely see Buck in a bosal unless the horse is at least 5.