Does a dramatica storyform dictate how the RS throughline progresses? eg for a success good story, does the RS have to mirror this and show a relationship building into a happy ending?
No. You can have a Success/Good where the RS ends “unhappily” or with the characters apart. It’s an interesting way to make the ending feel more nuanced. I believe one example of this is La La Land.
(Note, the storyform does dictate the RS signpost progression, of course, but I think that’s different than what you meant. )