Modified choke is a good "tweener". A "full" would be my choice for turkey or ducks. An "improved" for dove and quail. Be sure to note the inscribed labeling on the choke tube which should note restrictions relative to using steel shot.

Small game loads for hunting critters such as rabbits and squirrels ... usually a #6 shot size is a good choice. This goes for .410 on up to 12 ga. No need to even think about a 10 ga. , unless you are a glutten for punishment !

No. 6 shot is also a good size for ducks and pheasant. For doves and other smaller birds such as quail or woodcock I use #8. Lots of my buddies use #7 1/2.

For larger "small game" such as larger birds such as geese or turkey, a #4 or #5 is a better choice.

Clean killing with shot is also a distance issue. Have to remember that the energy in the entire shot load is divided more or less evenly to each individual shot. The smaller the shot, the less down range energy that each "bb" will have. While a "Rifled Slug" or "OO Buck" might cleanly kill a deer at 75 yards or so, the "outer" limits for a typical shot shell, correctly selected for the size game, is going to be about 40 yards or so.