I would say the ratio should be 1 looker to 10 feeders. I have read that you don't have to use that many decoys in the late season because the geese are used to seeing huge spreads and tend to stay away, but I was out there yesterday and we had a lot of geese come over and circle once and then leave. We where using a dozen shells and a dozen silos. I was hidden very well, so I don't think the geese saw me. I am taking out every thing I have next week and I will tell you how I did.