Trailer Training Fjord Gelding - Avoiding the Butt Bar

This Fjord gelding does not want to be locked in the trailer. He walks into the trailer, but is not committed to going in beyond the butt bar to avoid being locked in. I work on pressing him to make a decision to stand quietly in place and then reward him for standing quietly in place.
He has several evasion tactics: he puts his head down as he enters the trailer and gets "stuck" under the chest bar, so I manage his head and stay on top of him to tell him to keep his head up, he dances back and forth so I push him to step forward and stand in place. It's paying attention to these seemingly small details that make a difference in his progress.