Update - some additional information on the shot
I talked with a local shortstop a few minutes ago about the shot. He was there yesterday when the shot was shown to us on a Diamond table where the corner pocket is a bit too tight for two balls to be placed in the pocket. He told me that he had tried it on a nearby Gold Crown and had been unable to pull the shot off on the Gold Crown. He explained that the slate on the Gold Crown doesn't go as deep into the pocket as the slate on the Diamond and it's also beveled on the edge. When I asked him what percentage of the time he could dig the ball out on the Diamond table, he said he'd been able to do it 70% - 80% of the time. He said he'd be happy to bet even money on making the shot on a Diamond.
So from this additional information, it seems clear that you would have to test the shot on a table before trying it in a game or as a proposition bet. The shot seems to work on Diamond tables and given the widespread use of Diamond tables, it seems to me to be a worthwhile shot to add to your arsenal. If you are better than 50% to make the shot and get safe, you might try it in situations that are not desperation level situations.