Wanted to post back about my results.
Did not feel like waiting on a file to arrive so I used one of the small grinding stones on my knockoff Dremel (see photo below) to take the dent/lip off the edge of the guide. I went really slow and with a light touch and kept checking it with my fingernail in between passes. It took maybe 30 seconds of total grinding to make sure it was nice and smooth.
I then fired up the game and kept letting the ball drain and on the first try, without doing anything else...IT WENT 20 FOR FREAKING 20 ON AUTO LAUNCHES!!! I could not believe it. I then started trooper multi ball and it immediately loaded all three balls perfectly, which has happened maybe 5 times total since I have owned the machine.
For the record, I had previously tried all the other fixes including the more powerful coil and shimming the guide and the best it had ever done was maybe 65% with all misses being low.
Thanks so much to creepykenny for the fix and to Tranquilize for the suggestion to use something else to file it down.
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