Well, he needs 3, so he'd probably want to shoot the 8 straight-back, the 4 straight-back, then either the 6 or the 1. The 8 ball should be as good now as it was when it was the 6 ball, right?
Doc
No, not the same, and because of opposite reasons. Now you are the trailer 2 to 3, and all the reasons the leader would shoot the 8 are all the reasons why you wouldnt want to shoot the 8 if you could help it. All the things that were working for you when you were ahead, now will work against you now that you are behind.
As I cited, the 8 ball is the optimum ball on this particular layout. When you are ahead you would want to try and use that ball up for yourself. However, when you are behind you would like to try and find an option ball that is slightly out of play, but with relatively the same amount of difficulty so that you can save the "good" 8 ball to perhaps continue your run, or be a part of a later part of your run, or at the least if you miss, be a part of a dangerous open layout that will represent a real threat to the player that is ahead.
You have to forego the worry that your choice could also present more opportunities for your opponent. That is true, but that danger is compensated for by the fact that you can get all the way out if he fails. It is risky, but worth it because you are keeping constant pressure up due to the open fertile table.
That said, and for the above reasons I would bank the 6 straight back medium speed and have the 8 ball cross corner or cross side. (The same type of shot like the 1 ball that Cowboy Dennis wanted to shoot in the previous situation. Many more reasons to shoot it now rather than then.)
Shooting the 6 which is the main "blocker" ball to the other balls, completely opens up the table for the other 3 balls. The exact reason why you wouldnt want to do it when you were ahead. You dont want to open the table up when you have a lead.
I learned this lesson well from a master, Bugs Rucker. Many times I would have a lead on him and I would try to lock up and shut down the table for bank opportunities. Bugs would always find the balls that would most foil my efforts, shoot at them and keep the table open -- if he needed it open.
Like a crossover straight back where he sent the cue ball into a cluster, or a cross over cross corner where instead of going up table safe he would hurl the cue ball into the rear of the stack. Or just bank at the balls that were blocking cross corners or cross sides.
Conversely, if you are ahead these are the balls that you try to leave right where they are at.
Beard
Plus Doc, one more axiom. If possible I only want to shoot at ONE straight back in a row. Not two or three. If I am fortunate enough to make a straight back I would like my reward to be a cross corner or a cross side, not another straight back.