I've skimmed through the thread, so my bad if this has been mentioned previously...but what about this shot do you struggle with - potting or getting enough backspin?
If potting then it's usually how you transition from regular alignment to jacked up alignment. Mirrors, lots of mirrors! Will help with this at home. Or you can video yourself and overlay some lines to see where you're going off line in the transition to jacking up.
If you struggle with getting enough draw then I believe this is an easier fix. Simply hit as low as the cushion allows with a punchy type stroke. Then practice. Lots and lots of practice.
Here we all are sounding like absolute professionals, but make no mistakes, this is a very tough shot and one that even the best in the world wouldn't enjoy playing.