Ted, I start pretty much all kids in the duck marsh with a Mossberg 500 youth model, and Remington Express Steel loads in 2.75 #4's. Parent gets the license, I'll pick up the rest.
I am an entirely average shot. Time and tide what all...
We watch the distance, work on ID, and work to get the pellets up front. Geese are shot on the incoming, not the outgoing. I am definately not in the long and tall shot crowd. That's just a bad idea promoted by ammo companies.
A Stevens 311 is crude, but also elegant in a functional way.
My views on waterfowling have changed quite a bit, mostly because few 17 year olds near me can spend $50.00 to shoot their first goose. 15$ Fed stamp, $12.00 shells, 15$ state license, $5 state stamp, etc.
I have found that starting them with 1 shell, and working up to two, really helps their progress. Oh, and ear plugs. Gotta wear those around me.
If I had a 311, and I could confirm it safe for modern OTC steel shot chamber pressures, I'd do as I said, and use wads to change my pattern for the uplands.