If you do any sort of gold panning then you need to recognize the importance of properly classifying your material before processing it in any capacity. When sluicing, particularly at home with a recirculation system, classifying will increase you recovery greatly as same sized particles allow the gold to settle out much easier due to density and displacement properties. It will not battle with black sands as much either. Happy explorations in Nature!
The only way they could be improved would be to make 'em bucket circumference.