In addition to what Brian has suggested, I think you might find a 'Today' perspective works best in context mode. It will also sync to the iPhone version of OmniFocus, while project contexts currently do not. Here is a snapshot of mine, although I will add that I do not hide the sidebar as you have asked about. I find it helpful to have the contexts visible in the Sidebar so I can click on one or more contexts to focus my attention, similar to how one would click on tags in Thing's Today view.
