Cheers Headwax, you are quite right, it is a bit too smooth. What makes it so difficult to achieve a really accurate cycle is that you don't have full control over every aspect of a Figure in Sequence mode. For example, you can't change the relative vertical location of the Figure's root bone, so the Figure is locked in place, which makes defining the leg action that much more difficult, if body motion is to be taken into account. I suppose it would be possible to build a pair of angled bones from the base bone, kinda like a spring, and have all other bones sprout from these. I will see if this works better, and hopefully get a bit more undulation in the spine.
I plan to have the "dog" go from a walk to a trot to a flat-out sprint, though I may be being a bit over ambitious again. Up to this point I have not used any reference images or videos in constructing this, but I might need to search for a couple of dog/cat/horse running vids to pick apart the action for the faster gaits. So far there is around 12 hours work in this, not including render time, so I am very aware of how fast the deadline approacheth.