hehehe, the spinning on a front-leg target to learn to swing his butt is exactly what I'm doing with Paris at the moment to be able to solidify our left turns in heel work! It's what I was talking about with Kalamama how doing separate exercises for teaching the left and right turns etc; this video perfectly demonstrates what I'm teaching for the left turn (the 'swing yur butt' game! heh)
I have seen the gym ball work before, and I've even seen a great dane up on a massive one too!!! LOL.