Normally I use fluid story, fixed sidebar. But then six seventh of my screen are used for the story and one seventh is used for the sidebar.
When I change it to fixed story, fluid sidebar, then three fourth of the screen are used for the sidebar and only one fourth for the story.
All the settings for "Story right", "Story width" and so on stay the same.
It would be nice if I could manually change the width of the sidebar and then the rest of the screen will automatically be used for the story, or vice versa.