Not sure what you mean by break-in here. The gun should be reliable out of the gate. When I had a redhead in 12g, it was pretty difficult to break open and even after thousands rounds was still pretty difficult to open. On the other hand, a friend has a Huglu that falls open when you just push on the lever. Best I can figure is these tend to vary quite a bit as they come from the factory.
As for chokes, pattern it first and see how it does. If the factory chokes pattern well, you probably don't need to buy any additional chokes unless you simply want to (e.g., you like a certain look). If you don't like how it patterns, then I would investigate some third party chokes. Standard beretta/benelli chokes fit these guns, so you'll have an ample selection of chokes to choose from. For loads, generally anything from 7 1/2 to 9 will work. For longer-distance shooting (some stations on a clays course, handicap trap for S&G with a 20gauge, etc.) you'd look to 7 1/2, for anything shorter (skeet for sure, standard trap/clays) go with 8 or 9.
