Full Strap will be a good choice to get your canvasbacks for sure, especially if you’re willing to give up your other ducks to get them. There’s times/locations you can pretty much guarantee the canvasback, but that may be all you shoot. It’s pretty easy to target them specifically, but that often pigeon holes you for others. As far as shovelers and ringnecks, it just depends, mainly on water level at that time of year. Catahoula may be 10-15ft deep by then, but that generally only increases your canvasback chances as well as ringnecks sometimes. Blue wing is going to be a rarity generally, but possible. Don’t count on that.