Taking another look at the example site, to try and get a better idea of your intentions, I'm thinking grid probably isn't the best tool for the
header|content|sidebar|footer portion of the layout, as the header and sidebar there are fixed and not in the flow, just the content is.
Though grid may be good for the content of the content block, if it's anything like that site.
On a side note I always think that designing a layout without having the content in there is folly, as it should be the content that defines an element's volume which influences the layout. When it's added after the game changes.