I was going to stay out of this discussion as I had already posted my opinion earlier, however I was inveigled to get back in from a few PM'ers who wanted my take on the latest discussion.
First I want to say, just to be sure, I shot the shot over and over on my table and I did discover a few things.
The setup was that the q ball is 1/4 diamond over from the middle diamond and a chalk's width from the cushion. The first time I shot my choice, rolling softly into the back ball, I sold out! But I knew something was wrong because I had shot this shot with success many times before. Then I realized what I had done wrong by not thinking the shot thru. Going directly at the fullness of the bottom ball, ie., hitting it full in the face will sell out. Reason: That option provides the minimum amount of resistance to the bottom ball from the 2 above it, and thereby deflects off of them to the right and sells out.
But, by hitting the bottom ball SLIGHTLY off center to the right will result in the bottom ball being acted upon with the most amount of the weight and resistance of the two upper balls, enough so that the bottom ball will stick to the upper two and stay frozen to the Q ball.
Now unless you know that unusual quirk of physics, and few players figure to do so, rolling up to the back ball is a bad idea. (drawing off of the back ball is also a stiff because there is no way you can get enough draw to move the cue back backwards toward the cushion without the head ball returning to that end of the table.)
The only reason I remembered how to roll up to the bottom ball was just a matter of having had to do it so many, many times in my bank career.
Now with all that said, let's assume that you are not comfortable with rolling up to the bottom ball, especially because you are not familiar with using the weight of the two front balls move, then I can certainly see someone taking a deliberate scratch; and the scratch that I would take would be to push the cue ball even closer to the cushion and over to the left another inch or so in order to completely eliminate the barely doable, roll up to the bottom ball angle. This move often results in confusing your opponent and he may panic and do something stupid.
Now it is very surprising that Dr Bill has endorsed taking a scratch in this spot, since he chastised me for suggesting taking a scratch in an earlier bank pool layout. Unfortunately, I dont remember when or what particular layout that involved, so I cant compare situations. One of my PM guys reminded me that he once did that. ???
I am totally against, however, the Ghosts suggestion to take a scratch up against the bottom ball. That situation is easily handled by playing off of the bottom ball into the long rail and returning to the middle of the short rail, gaining nothing.
The worst situation for you if you take a table scratch is if your opponent takes one back, and I just dont see that happening -- not in bank pool. Everytime I have ever done on an open table and not off of a corner hook, my opponent goes on tilt and tries to do something other than returning the scratch -- and thereby playing into my strategy. It would take a hard core guy to return the scratch. I would of course.
Even if he takes a scratch back, remember now two more balls have been spotted up and it now becomes much easier to clip off of the bottom ball with a little english and go to the long rail and return to a place under those balls in the middle of the short rail.
Phew! That gave me a headache. I knew I shoulda left this discussion alone!
Beard