what would help more seedman is if you get some 1" x1_16,1"1_12x 1_16 flat and make 2 louvres across the round hole sieve to force the air through it. weld the flat on a angle to the round hole sieve. you can then adjust your wind deflectors to-wards the back of the sieves and i believe you will be supprised in the increase in capacity and cleaning.the late 850and860s here in australia used a fixed lip sieve but we found the modified round hole far better. john