I didn't have a notched wedge like in the video. Used a regular wedge and put some electrical tape on it for cushion. I was pretty timid with the pounding at first, but wasn't denting anything so hit it harder. I couldn't tell that it was moving at all, but it definitely moved enough to make the latch work better.
Before, I could see that it was slightly off center. Had to really slam it to make it close and it was difficult to close from inside. Works great now.