I used to get all excited about patterning until it finally became obvious to me that 2 dimensional patterns have only a loose correlation to what the target experiences as the shot cloud goes by.
Zutz and Oberfell and Thompson all have serious pictures of patterns with obvious holes in them. Zutz holds a clay target over the pattern void to illustrate the concept that a target can slip right through there without so much as a nick.
Well... during the passage of the shot cloud the target moves, unless of course you only shoot at fixed paper sheets.
No moving target ever sees the same pattern as you see on a pattern sheet unless the only motion is directly along the shot flight axis.
Shotgunning is an exercise in probability not unlike gambling.
A few patterns are useful to illustrate the range limitations of the load, and yes it's directly and most importantly related to overall density and not so much to perceived distribution.
Your target is moving through 3D space, it experiences a passing swarm of shot, and the path it takes through the cloud and how many pellets it might collect on the way is at present not measureable.
