Rusty..........I got out of the army at Homestead AFB back in the seventies......worked in south FL in the early 80's.......the duck hunting was great around Kissame and Okachobie..........
I've never owned a 3" or 3 1/2 inch 12 gauge, always found the 2 3/4" would do anything I wanted to do if I did my part........
Certainly the 3" and 3 1/2 inch will put more shot in the air........but, the price of the shell is very high, and the recoil is not near as comfortable as the 2 3/4............. the actions are longer so usually slower......and less reliable....
Bigger isn't always better........seems the trend these days is to get the latest, biggest whizbanger going...........then take the beating shooting it.......fact is........in almost all situations, the old tried and true will do the job just as well, more comfortably, and usually cheaper.........