Use the Improved Cylinder choke in the barrel. Since the receiver isn't drilled and tapped for a scope mount, you can get that done and have a scope base put on. Or you can get those clip on fiber optic rifle sights that attach to the rib.
However, a field gun with 28'' barrel, and the Nova is already an 8 lb gun is quite heavy and unwieldy to be humping around in the bush. Its best purpose is for waterfowl and clays in my opinion. I brought it grouse hunting once, it wasn't the best choice for weight and length. YMMV