RE: Chesapeake sea ducks
It's way to early for sea ducks especially on the Chessy. Besides IMHO unless it's a exceptionally cold winter you'll be shooting scooters and little else for the most part.
IMHO the best seaduck hunting is from Rhode Island & north, with Maine being the best with Mass a close second. For me I consider eider and old squaw seaducks and look at scooters like coot.