The best answers you've gotten above are to pattern what you have now with your intended load and stay away from full and tighter chokes was steel. Steel and choke combinations take patterning to truly know what you're dealing with. The same as really true of lead, but it's slightly less critical. I actually use the same choke for everything steel, but I change the shot size depending on the bird size and distance. The shot size change actually causes the overall pattern to get tighter as pellet sizes increase which equals bigger Birds a longer range. Only patterning will tell you what you need. Light modified or skeet 2 is one of my favorites in standard bore 12 gauge like a Remington 870 or 1100. That will vary a little bit with overboard shotguns.