The way the cooldown works, I actually think I move farther, faster, if I just use the first word only. It charges up very quickly, much faster than the full, three-word shout. Not only that, but the full three words only moves your character another 20% or so.
So there's the question, is it actually faster to use Wuld three times, then Wuld Na Kest?
I think so. Can anyone figure a way to measure this? I would love to be able to say something with objective precision.