...i don't feel i'm getting the right movement out of the new leader,and i'd like to keep it the size it is now...
I didn't see this right away, DM. If you want to add some movement to the new leader, now may be a good time: the thinner the wood is, the more easily it will bend. But I would study it first to decide just what movement you want to add.
As for the "right movement" -- right for this tree -- that's a perception to be learned, and I'm still learning it myself. I start by studying the tree to see what movement is already there; then I try to visualize what I'll have if I simply accentuate what's already there. Sometimes that's enough. Other times, I decide it needs more, and that's where one must develop whatever eye for art one has.
One thing that helps a lot is a good photo-editing program. (I use Photoshop, but there are many others.) Photoshop lets me "try out" various ideas without actually doing anything to the tree.
I'm in the process of that right now, as a matter of fact, and also with a shimpaku. I've worked up 3 virts so far, and am working on 2 more. Once I'm done with all 5, I plan to post them here on B-nut and ask for feedback. Give me a few days, and then you'll be able to see an example of what I'm talking about. And feel free to give feedback; there's always the chance you'll see something I don't.
One more thought. Whenever you are ready to actually bend the new leader, I would wrap it in raffia first. That will lessen the chance of what one friend of mine calls "accidental pruning!" You don't always need raffia, but this is your future leader.