This is a great question!
Although I certainly wouldn't be against starting with a storyform / random gists just for fun, my process is kind of the opposite of that.
First, I come up with a story idea, and develop it for as long as possible without using Dramatica! Must let the Muse have free reign!!! (Exception: once you learn Dramatica, it's basically impossible to not think about the four throughlines. OS, MC and IC seem to just show up and I can't help recognizing them for what they are, and RS becomes apparent soon after. Luckily, that knowledge doesn't hinder the Muse at all. I do try hard not to let my inevitable Domain ideas get set in stone though.)
In development, I try to resist storyforming for as long as I can. At some point, I just won't be able to resist anymore because some common elements become apparent -- stuff that I didn't consciously make common to fit any storyform, but it's there. For me, that's the right time to try storyforming. This part is insanely fun because you get to see how your ideas already fit a proper storyform, at least partially (like: "holy cow there is Obligation and Help in almost every scene!"). And it often feels like Dramatica is reading your mind; I guess in a way it is.
After that, I keep an open mind about the storyform -- I may think I have the right one but be wrong. I always save lots of copies of different storyform variations. Often Resolve, Outcome and Judgement take me a while to determine; it's like I'm keeping my options open for how the end will turn out.