I've included 3 sample HTML files here, showing how the same markup can be used and how the CSS and JS tries to intelligently make the best use of the available space. The charts resize when resizing the browser. The yellow and red threshold values can be set at the top of the JS file.

Here's a preview of these pages in action:

http://backups-ui.blackantmedia.com/3_x_3.html

http://backups-ui.blackantmedia.com/4_x_4.html

http://backups-ui.blackantmedia.com/5_x_mixed.html