Mitch,
As I recall this shot, the players were on a break which afforded the opportunity for plenty of discussion by the commentators before the shot. Dr Bills main thought behind shooting the two railer was that he could "naturally" attain optimum CB position going three rails (short-long-long) to the middle of the head rail, thereby leaving NADA (always a worthwhile goal) should he miss.
I think you have two chances of holding the CB on the foot rail, slim and none.:lol:lol.
Chances of leaving a cross corner bank or a two railer out of the top left corner loom pretty high also. All in all, trying to hold that CB to the bottom rail would not be advisable IMHO. But hey, I could be overthinking this.