Hello owlsden
I will be in inkexplosion if You will be there, let me know i will take a tool that fix the hole in 2 minutes( its a hand tool) . I fixed this 100 times and have the exact size. Will be Glad to fix it for You, ando of You aré going to the show dont spend time and Money fixing it!
And please dont try to file it ir dremel it! It will maje a sloppy hole and it will be very difficult to fix!
Roman