Shift Pro allows you to give every Post and Page its own layout. Layouts set this way will override the layout set in the Customizer.
To change a Post's layout:
- Visit the Posts menu
- Locate and click on the Post you want to change layout of
- Scroll down the page until you see the Layout box
- Use the dropdown menu to select the layout you want to use for this Post
- Scroll up the page and click the Update button to save your new layout
Your Post will now use the newly selected layout.