Based on everything I've read, 40 yds on Canada geese with a 1oz - 3.1/4dr steel load is improbable, especially from unchoked barrels. Even if you pattern is dense enough, penetration might be getting questionable, and that's assuming you are not dealing with the larger breeds of Canadas. The only way for you to know for sure is to try the load in your gun, testing both pattern and penetration.
Frankly, for geese, I favour bismuth or NiceShot. One of my hunting partners is quite happy with either bismuth or Nice Shot #4s on lesser Canadas and Snows, but even with his choked 12ga flinter and 1.1/4oz loads, I don't think he pushes it to 40yds. I still want to try to see if I can work up a steel load I'm confident in for ducks, but until then, I'm working through my stock of old-production #4 bismuth (about like #5 lead).
Good luck,
Joel