I fear what you'll find is that the bulk of bluewings and greenwings winter in different parts of the country. Throughout much of Louisiana, greenwings are the number one duck in the season's bag, but bluewings are going to be scarce. I know that here in SWLA, my parties' second split totals included 205 greenwings but only 14 bluewings, so while shooting buster greenwings is likely, the odds are worse than slim against getting a mounting quality bluewing to go with them. And it's been my impression that South Florida is about the opposite, if not worse. troutman is encouraged to correct me if I'm wrong about that.
If it were me, I'd take a hard look at what's being killed by outfits hunting the mouth of the Mississippi River, as they should have plenty of greenwings and, it's again been my impression, that they also kill considerably more bluewings than we do here to their west. That, and a mouth of the river hunt is a unique experience that should probably be on every serious waterfowler's bucket list.
If you think I'm wrong, you might be right.