I use an improved on my 30 inch barrels. I use improved modified on my short barrel gun and you must be on close but good long. Check Comp-n-choke extended ported chokes they are a great addition.
I shoot Improved cylinder and light modified. Can kill them out to 60 yards with that setup. Also I shoot Fiocchi golden pheasant 7.5’s. This is my 28 gauge setup. If I shoot 20 gauge, rarely, then i shoot IC. If it’s really windy then i do bump it up to a light mod. Same principle for my 28 with the wind I’ll go LM and M in high winds. No need for me to go any tighter.
In PA I use IC/Mod. 7.5 is my first shot and 6 is my second. When I go out west for wild birds I used 3 inch shells and my chokes are Mod/Full and first shot is #6 and second is #5