The 28 is my favorite gauge, I had my daughters shooting my Rem 1100 28ga when they were 10, not that they were any good at it, but it wasn't because of the recoil. I also load all my 20 gauge shells with 3/4oz payloads of shot, just like the 28, they will function my 20ga 1100 and have the same felt recoil of a 28 if that might be a road you could go down also. If you plan on reloading you can even make the 28 with lighter loads.
I don't have any experience good bad or indifferent with the Weatherby shotguns, I believe they are recoil operated, not gas, and they will probably have a bit more felt recoil than a gas operated gun like the 1100 or some Beretta autos. If you can get to a range that will let you try guns that would be my advice on what to get.