Ya i just started doing them on flatboxes to make it easier on kinks.... for one make sure your ski is right on the edge of the box like your going to K fed or front switchup, and i dont jump until my body is almost facing forward. And the other key is when you jump pull your knees up hard or its really tough to make it past 2sev. And when i do them i dont 2sev on and i do it front side. Depending on what foot forward you are, say left foot as soon as you hop on the box jump backside if you spin right and that helps get you around.