Robi,

Those look like the glass RBS battens. I have the same thing in carbon. The heavy #2 and 3 are used for higher wind ranges. Depending on your weight, you would use them in winds 15 and over. When you use them you want to use both #2 and 3. Keep the batten tension fairly tight on the top three battens. I don't know of anyone using both at the same time. But you guys are approaching the windy hurricane season <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />
Ken