I would put them out 10 to20 yards.

There are times when a guy pretty much knows what direction the birds will come from in a left to right (or vice versa) situation. If you are fortunate to know that, then I don't think distance is as critical as long as they set out within range. What I do in that situation is set the dekes to thefar side of me so it forces the birds to cross in front of me on their way to inspect the decoys. Normally they never know what hit'em.