No flat 1hbhs coming out of Kevo's class.Spacing is critical on the 1HBH. It might be the most critical element of learning to hit it really well.
As for the shoulder uncoiling it can happen in a limited fashion in the vertical plane as well as the horizontal plane.
When I teach someone a 1HBH for the first time, especially beginners, we usually don't use much torso or shoulder rotation. It's mostly a down - up motion sort of like swinging a pail of water. It's very simple, but quite effective and the directional control is outstanding. Then as we progress we "wind up" more of the body in preparation for the shot and naturally start to gain more power and spin.
"As for the shoulder uncoiling it can happen in a limited fashion in the vertical plane as well as the horizontal plane."
Not sure I follow here. ???