Many of us in BC use .410's, singles or bolts, mostly, for grouse - on the ground or sitting in trees.
I like the 2 1/2" #6's as they pattern well enough to hit flying birds. The 3" are not good in my gun - next to useless as they have too small a killing circle at 25 yards (6") and too large a wounding circle, 3' due to the damaged pellets from too long a shot column.
The the 1/2oz 6's, I get about an 18" killing pattern, which works well for me.