It has been my experience that the bigger shot in blends will hold more to the core of the pattern, I don't know the explanation for this but believe the smaller 9's more or less draft behind the larger shot, Reloader could give you a better explanation of this and you might PM him for it. All of my experience has been with hand loads of 1 once of 9's under 5/8 ounce of 8's but should shoot good out of that .562 Indian Creek. I'm running a duplex of 8.5 x 9's this year but it's just to use up some 8.5's I have on hand and then I will only load 9's from here on out. I also stack larger shot on top of smaller when duplexing and don't mix shot.