Shot string can work for or against you. From the high speed photos I've seen the leading edge of the shot stream is center mass and tapers out like a cone rearward. There seems to be a reverse cone effect towards the rear of the stream but much less well defined. Flyers or out laying pellets can be so unpredictable.
In clay targets I always figured when I cut the nose off a bird I was using the edge of the shot string. Crushed targets were centered. Those birds which split in half were most likely hit by out laying pellets and were all sheer luck. I'm am sure you could figure out the distance a clay target or bird travels in the time the entire shot string takes to fly by it. I've read 2"-10" depending on angle and speed of shot and bird. Having heard a lot of pellets rain down in the dove field I figure at 25 yards it is a few inches because at a hundred plus yards, when spent, the stream takes several seconds to fall completely.
So our most commonly used tool to determine load effectiveness only gives us a two dimensional view of what is a 3-d world. Not perfect, but it does give us a lot of information. And I wonder if what it can't tell us is that big of a deal? Every pattern is slightly different. Those flyers in one pattern are somewhere else in the next, but center density should be fairly constant. And we should mostly be using center density most of the time.
Based on those assumptions that is a very good looking pattern. I'd use something more open if closer, if I could, but sometimes you have to accept that there is not one size fits all conditions in shooting.
