I tried the 10:1 scale but with bad results. I created a 1" diameter ball in 10:1 scale (using cm) and then created a spiral slide. I attached gravity to the ball, assigned passive to slide and it wouldn't solve the animation. Without the slide, the ball fell realistically. However, it didn't seem to like interacting with other objects. When I increased the size of the slide, dramatically, Maya solved the animation. But if I increase the size of the objects, I'm back to square 1, lol.