In my opinion -- no. Storyweaver is great for bottom-up brainstorming, generating story material and corralling disparate ideas. It's a much more organic, "muse-centric" approach. But if you already know 80 percent of your story, a lot of what you'll be doing is cutting and pasting. (To get an idea of what's in storyweaver, you could read Melanie's book How to Write a Novel Step by Step -- I think that's just Storyweaver in book form).
I don't think there's anything in there about the crucial element for example.
So exactly how far along are you? Are you down to one storyform and do you know what that is? If so, as long as you're not contemplating changing the storyform, you should have what you need to outline. (It might be a blessing to be forced to stick with the same storyform while you draft lol).
If it's just the Crucial Element you're looking for just post the storyform here (or DM me) and any of us can tell you.
(anyway, this is the formula):
If the MC is change and the outcome is success, the MC crucial element is the same as the MC problem.
If the MC is change and the outcome is failure, the MC crucial element is the same as the MC solution.
If the MC is steadfast and the growth is stop, the MC crucial element is the same as the MC Symptom.
If the MC is steadfast and the growth is start, the MC crucial element is the same as the MC Response.