Umm, those were ringers (maybe canvasbacks or bluebills on occasion). The dekes were likely Goldeneye, bluebills, and ringers. It sounds like a buddy of mine's setup, too....but plenty of other folks do it. I doubt you were seeing massed flights of wooducks on big water....plenty there, but they just don't usually mess with a line or fly in groups. Ringers make the most noise when spilling air, but cans and bluebills can sound like a jet hitting the afterburner, too. Goldeneys are also called whistlers. They usually make a whistling sound in flight because of some wing feathers, or something. You use a line of divers backwards to the way you set up for puddlers, at least regarding the wind, and divers like to do things in flight with relation to other ducks that puddlers typically don't do.
Here's a thought: Let the ducks work and decoy.