I opened the full choke on my 1926 field grade 16 gauge model 12 because the original full choke was worthless for what I needed the gun for. It patterned like s%#t with spreaders too, polywads and hand loads. Shooting birds over pretty good pointing dogs…I never once needed the full choke, then again, “pillow casing” hard earned game birds was never my thing. I just don’t get my jollies destroying game birds.
I opened the choke to .010 and never looked back. No hard feelings either. It’s my gun and I’ll do what I need to it for it to work for me. I’ve taken limits of pheasants, Chukars, huns, Sharptails, ruffies, blues, & quail (bobs & valley).
Pattern the gun with spreaders and see what it prints. My feeling is that you’ll find what I did, the spreader patterns just aren’t gonna hack it.
See if one of those barrel sets can be fitted, if it’s possible, go for it. If that’s not an option, adjust that choke for what would work best for you.