CreeDo said:the long straight shot is one of the most difficult shots, not just the hardest straight shot. I see a few people claiming they rifle it in with regularity but I'll need video before I buy that. The difficulty of the shot using Bob Jewett's system is almost a 20. I dunno how to calculate the bank, but it's true that it's a bigger pocket opening (which is not shown on the diagram... the diagram should have the side pockets at least another half ball wider, or the corners smaller).
I wish I could remember and find what Bob Jewett said about difficult angles, if I remember it correctly he said two particular angles give the least margin for error, and straight-in was one of them. Maybe I'm wrong but I did try these long straight shots several times and it's really missable.
I agree that the long straight-in shot is more difficult than some people suggest (unless you hit a million of them of course), but if you had the same distance and it was a cut shot, wouldn't it be even more difficult?