RE: pass shooting
Pass shooting you're not going to get as many close up shots, so Modified with BB's, as fast a load with as heavy a load as your shogun will shoot. I use BB's on all goose and late season northern ducks in recent years with modified choke. They'll penetrate the heavy feathers and bring them down with a good shot most of the time.
We had lots of opportunity for such shooting over decoys earlier with Canada Giants and later with large flocks of Snows, Blues and Lesser (Cackler) Canadas in ND pass shooting them. We did very well with the combinations I mentioned.