We have Calmer Stalk rolls on our JD 893 head and bale 150-200 stalk bales a year.  We use a batwing 15' mower and mow the stalk stubble down before raking with a V-style rake.  We found it very difficult to bring the stalk material 4-5 rows into the center windrow with the 32,000 population picket fence blocking the flow.  By mowing down the stubble, we also get several more bales per acre.