Just for grins and giggles...him on one of his reining horses a few decades ago...
Rio Leo Superstar
Anyway, GH, I think all your questions have been answered, I just did want to touch on the weight thing. A good, sturdy horse, regardless of height, should be able to carry you easily if you ride well. Where the trouble starts is with folks (regardless of size) that flop around up there and ride about like a sack of potatoes, completely off balance with no absorbing the shock of the gait.
Someone who sits light, regardless of their actual physical weight, can ride smaller horses than someone physically lighter that bounces and flops.
Anyway, I don't compete in reining, but I do ride horses that can do most of the maneuvers...rollbacks are awesome but I think I am most proud when I get a nice balanced circle with good rate.