There is more truth to this than many realize. Larger pellets don't do a lot more damage. Increased number of pellet strikes to the meat cause a lot more damage. That is the reason that when I shoot #6 it is generally a 1 oz or 1 1/8 oz load.I've definitely seen my dad and his buddies shoot old 3.5" turkey loads at late season roosters.
I usually shoot 3" steel 3's myself.
I personally don't think it matters much. Shooting them with a heavier duck load isn't necessarily more meat damage than a denser pattern of lead 6's.