don't you know you have to have 5 or 6,000 dollars worth of decoys
. Birds don't decoy to silos. I only use about a dozen and a half that I made up myself but we don't get large flocks of ducks, mostly small 5-10 birds in each flock. I would say match the size of the flocks that your are hunting and than just about double it. I wouldn't use more than 3 or 4 dozen. i read a post somewhere where a hunter drilled a small hole in the bottom of the head of some floaters, inserting a small dowl to keep the decoy up right, used them for field hunting and used them on the water, didn't leak. I just can't justify spending big bucks for shells when silos will do the same thing.
Very easy to make a pattern. Get a small lamp with a large wattage bulb. Place a sheet of large paper against the wall. Place a decoy between the light and paper and adjust the light , closer or farther away, until you get the size you want and trace it. Transfer it to the material that your going to use and go at it.