Create a test page.
In the test page editing page, in the “Select Sidebar Layout for this page ” drop down list, try the various sidebar modes and test by previewing the page and shrinking your browser until the sidebar stack.
Try “Sidebar on Right” that should stack below, versus “Sidebar on right (stack on top)” that should stack above.
Aslo try “Sidebar on left” that should stack below, versus “Sidebar on Left (stack on top)” that should stack above.
Post a link to the test page when the option “Sidebar on Right” is selected