Like FS2K I'd go with the shotgun and #4 Buck.
I did some patterning with an 18"/cylinder choke,
results here - YMMV.
I also have a Win. '94 Trapper in .44 Mag (16" bbl, 9+1 capacity) but it's the shotgun that stands guard duty. My reasoning being that under stress I'd rather have a gun that just needs to be pointed "close enough" instead of being "aimed", also I'm more likely to inflict enough trama to stop the threat per shot-shell than per bullet or slug.