RE: How many decoys?
Hunting in VA.
For ducks: Typically, its around 6 mag black ducks, 6 mag mallards, few teal, few woodies, and the odd sprig and widgeon just to mix it up a bit. Depends where I am at. And its not always those numbers either. Often it is less. I don't think I have ever put out more than 15 blocks. Sometimes when I am in the right spot for it, I will put some geese up on the shore, or off to the side. I own, and on still, sunny days use, a floater and pole mounted Mojo. On cloudy, windy days...they stay in the boat.
Most important around here is the wind and the tide. I have slaughtered birds over three decoys before, but I sure feel undergunned sometimes when I try and pull that off.