First I would like to thank you guys for the patch-arrays you posted here! I knew I was doing something wrong, my chains kept breaking after 25ish, the (4) times I did go over 40 were pure dumb-luck and most of my shinys I caught were dumb0luck too. XP
Diesel: I don't know the answer to your question, but I might know where you can find your answer - room-hacking forums. The guys who modify games might have cracked the pokemon/patch distribution system. My educated guess is that there is a percentage of chance for the pkm being on the 1, 3, 4 or 4-away and this percentage is tied to the patch-array/ patch position (as in (x,y) coordinates).
Now I would like to add my 2 cents.
1st - It's a good idea to have copy the patch-arrays in an old notebook or in a few sheets of that special paper that has squares (instead of lines) all over it - dunno how you guys call it, English is my 2nd language and i have problems with specific vocabulary.
2nd - This is what made my chains go from 8ish to 25ish. Us girls have this thing called eye-liner, they come is all shapes, but there is this one that looks just like a regular pencil; since that have to draw line on human skin, the tip is really soft. I used one to draw a line between the 3-away and the 4-away radius so I can spot right away all the 4-away patches and whenever I want the screen to go back to it's pristine state, all it takes is a very gentle scrubbing with a Q-tip or a little ball of cotton and maybe a demaquilant if it's cold (or a drop of regullar cooking oil - the stuff the eye-liners are made off are all oil based). This one probably made you guys get huge anime-like sweatdrops, but hey, it works! *~*''