The patterning I've done tells me you can start to see differences between IC and MOD, and between MOD and FULL at about 10-15 yards. This is with loads containing standard wads and lead shot. I don't pattern steel loads at less than 30 yards.
Your wads must be different than most AB but there's no doubt of what you say ! Any kind of useful pattern needs a little more room , though !
Not sure if the curiosity is steel, lead or (?) specific, but, I've always found this article from Shooting Times interesting, hope you'll find it pertinent..... https://www.shootingtimes.com/editorial/longgun_reviews_st_headintheclouds_201002/99884
Those illustrations are fun to look at as the shot cloud starts to materialize into a useful pattern ! There's a question to the shooter though , do you know at what distance you'll be shooting , while hunting ? The other is TOF ( Time of Flight ) of the pellets , like Brister showed in his moving targets , pellets that were affected by set-back from to much velocity or lack of protection of the wad , were delayed as they slowed down quicker than the core pellets . Steel Shot didn't have this problem with his demonstration . The shorter shot strings of steel shot might slow down quicker than a higher density pellet but it will stay together longer , than most payloads . So , you can count on more pellet strikes to the target within a reasonable ......distance shooting !
I lost what i said. Linear rate of expansion starting at tip of barrel? Thats an educated guess from a guy who got As in calculus-based physics. I don't really know but that "sounds" believable. When I shot paper at 30 yards in my gun full and mod were pretty same same but the improved mod and IC had pellets outside 30 inch circle. Like shooting closer so I should choke down but I also miss sometimes twice. I like modified. The guy who posted real data and ranges. That looked like linear rate of expansion to me without crunching any numbers. Plz don't make me prove it thats differential equations. Actually you could draw a chart on graph paper and draw the line. Easy
Most fellas don't realize a shotgun will out shoot their ability ! Choke tubes are a Band-Aid for that problem , you can determine the distance of your ability and choose a choke tube that will give you , the maximum benefit of its pattern development , with several golden bb's !
I try hard to not overthink anything except decoy placement. 25 yards to the furthest one. Learn your gate and count steps. Two steps is 5 feet for me roughly. That takes a lot of guessing and thinking out of the shooting part.