Factory work fine, but they often do not give the very best.
Kind of like saying you can use a factory 308 heavy barrel for 1000 yard shooting, and sometimes you find a hummer, but typically if you want the best you have to go non factory.
Patterning is the big key, factory or aftermarket if you don't pattern you have no clue. YOu have to test ammo and or tweak reloads to get to the best and it never hurts a shot charge to run though a longer choke tube vs a shorter one.
Of course if they are all within 20 to 30 yards you could just do it all with 2.75 inch 6s and probably just leave the choke tube out...
