the 2 key balls on the break are the 1 ball and 2 ball.. putting the 2ball at the back makes it a random ball it flys around the table and gets kissed a lot... rest of balls can be placed to land in a certain position esp 2 and 3 ..least with the two ball at the back it makes rest of the rack random layout.
with one ball on the spot the top guys worked out to guarantee the wing ball and get the one ball to land over one of the top pockets near enough.. professionals have masters this..
with 9ball on the spot the wing ball guarantee is taken away.. sometimes the one ball goes in the side..so the next lowest ball is 2ball so if thats racked at the back it can land anywhere so thats good because doesn't matter where rest of the balls are place when racking..
so this the best version of 9ball. and the toughest.
You seem to think I said something different than I intended. In 9-Ball the 1 and 9 are pre assigned locations. Your saying include the 2 into that. Which leaves 720 different possible rack patterns. If you were given a scoresheet that was a race to 11, there would be a possible 22 games. For those 22 games a pattern would be given for each game, no repeating patterns. That way no one could complain about someone using the same pattern over and over. Each game would require skill to get out.
Through that you could then track break and runs tied to patterns and correlate which patterns are the easiest.