... The shot was putting the cue ball at a medium angle shooting the cue ball into the top left to draw directly to the short rail. ... .
I'm guessing you meant "shooting the object ball" above.
These are some of the ways I can think of, and you need to be able to play each of them:
Top left pocket, draw, above the 8, no cushion
Top left pocket, draw, above the 8, with right end cushion
Top left pocket, draw, above the 8, top long cushion only
Top left pocket, draw, above the 8, top long cushion, end cushion
Top left pocket, draw, below the 8, no cushion
(three more as above)
Top left pocket, draw, below the 8 -- all eight combinations above
Bottom left pocket, draw, all 16 combinations above
Top left pocket, cut to left, Z pattern, no end cushion
Top left pocket, cut to left, Z pattern, with end cushion
Top left pocket, cut to left. follow to top cushion then to below 8
Top left pocket, cut to left. follow to top cushion then to below 8, touch end cushion
Bottom left pocket, four shots above.
Top left pocket, left end then bottom long, six different cases
Same six cases for bottom left...
Follow to middle of left end rail for 16 different cases
Nearly straight into a left corner pocket and then spin out of that same corner for roughly 16 different cases
...
And then there is:
7 into top left pocket with lots of left english, hit on the top rail to the left of the side pocket, come back across the table nearly straight and slowly to the bottom rail, then the spin grabs and carries the ball down to the 8. There is a video of Corey doing this shot or something similar.
If you can't come close on any one of them after five tries you know what you need to work on.
I suppose you could make this layout into a drill: run out with 20 different starting patterns.