I did it again last night, this time on a 7' Diamond. I left about 1/4" to the rail instead of 1/8" this time. With the 1/8", the gutter would often pull the ball frozen when I wasn't looking, and I'd move it out before the shot. I decided to go through all 15 in succession, one attempt at each, and keep score. I got 8/15 success. Total balls pocketed was 65/90.
I didn't really like doing it this way because there was not a good rhythm to retry problem outs. Also on the ball return Diamond pro-am, I'd forget where the 2 ball went when the table was cleared... compared to the drop pocket GC I was on the prior day. Setting them up was trickier. Next time I think I'll just shoot each one over and over until I get sick of it, then go to the next. That's what I did the first two days and I felt I learned more.
The same shot of following the ball into the pocket got me again. I'll have to work on that, I think its not a good shot if the scratch percentage is so high.
Can't get by without blasting the Diamond pin-ball bounce. It really shows up on this drill.