You can lie down on a wet piece of cardboard and measure the impression to get your sit bone width. There are some detailed instructions somewhere around the forum on how to do this. My LBS has the meter. On this you sit on it leaning forward like you would be sitting on your saddle. This might be the way to do it on the cardboard test, also. I don't remember specifically so search for it or maybe someone else will comment.

You can go to Roadbikereview.com and read a lot of reviews on the saddles you are considering.