I wouldn't call myself a "pantser" normally; I'm probably more naturally a plotter (planning comes a lot easier than drafting). However, once I sit down to write the story, if I've planned it out too much it makes it way harder to write*. So I think my my normal process will fall about halfway in between -- some light planning of the whole story before starting the draft.
But with my current WIP I'm trying out a methodology that's much more like pantsing, where you plan only a few scenes in advance, and really try to surprise yourself as you're writing the first draft.
To get to the point of this post, what's really amazed me is how useful a tool like Narrative First's Subtext is even when writing this way. Of course, I had to figure out the storyform first, which took a while when mostly pantsing (I was most of the way into Act 1 when I figured it out). But once I had that I was amazed at how well the PSR beats fit what I'd written before. Subtext's ability to breakdown the signposts into PSR items, them move the beats around, change the players involved, etc. really helped visualize the flow of the story I'd already written -- and what was coming up.
So now (I'm about halfway through Act 2) I can look at the next few upcoming beats and see how those align to the upcoming scene ideas. This is great for confidence (feeling like I'm on the right track because I'd already planned a huge predicament for everyone, and Subtext is saying "The cats are in a predicament"). It also helps me align the scene ideas to the PSR beats.
Then for the rest of the story that's further ahead, for which my ideas are much more vague, what I really like is looking at all the beats and just being able to sense how the feeling of them is right for that part of the story, even though I don't know what those beats will actually be. Like this:
Is IC Pongo really going to be "approaching doom" in Act 3? Maybe not, but I know for sure that something about that just feels right, as does the idea that his worth or worthiness will matter. And for some reason, it's easier to tap into this feeling with something like "approaching doom" than "The Future".
And I think my subconscious likes those upcoming gists, too. I get the sense that the Muse is sipping them like fine wine and rolling them around on her tongue, the same tongue she's eventually going to use to surprise me with a great idea (or maybe stick out at me and say "ha! you thought you knew where this story was going? try this!")
* mainly because I have too many ideas and expectations by that point of what the prose will sound like and how good the story is / will be. I'm way better off drafting when the story feels like big, empty, unexplored territory.