Thanks for the feedback. We’ll take it into consideration.
To be honest, the recommended way for using the vertical scroll is to not have a separator at all (you can enable/disable it from settings).
I just gave vertical scroll in Apple Books a look and I like it. But they took a more skeuomorphic approach and pages look like actual pages and they have a shadow underneath.
We’ll probably take a simpler approach but we’ll look into it.
Sometimes in vertical scroll the screen can be really messy if there is no propre separations between the panels and i do think that the ones used by Apple Books are the best size (apart for the design).