Okay I found the youtube video that I used to create my table runner. here is the url:
http://www.youtube.com/watch?v=u3k85E3lzfU
but I don't remember how wide I cut my background fabric, but my 3 strip set to place on top of the background fabric was equal to the size of the background strip. I hope this makes sense after you watch the video. Also the setting around each block I just made up as I went along, I did not per say have a pattern. I hope this helps.