If you are hunting small water and generally only see small groups of ducks on those bodies of water then a small decoy set is all you need. It looks unnatural if you go into those areas and throw out 6 dozen decoys. Motion is key IMO so throw out one Mojo and run a jerk rig. I kill plenty of birds in small swamps with 4 geese and maybe a dozen duck floaters with 4 feeders on a jerk rig and one spinner. The geese floaters or Magnums will draw their attention from a distance and then hitting that jerk rig to create ripples can hook them right in with no calling. Generally only hit them with greeting calls on the corners and then light feed calls or single quacks if they are facing directly at you. Later in the year less is more for calling especially volume wise. They can flair real quick if everyone in the blind starts high balling at them especially if they have been hearing that all season already