I prefer the file, but I don't knock anyone using dremel. I have tuned hi reeds up a half step with a file, no problem at all, though I was a bit nervous. All a matter of what someone is used to.
I commend you Bryan, I'd not have the patience to embark with a file.. I've had nothing but back luck with files, especially the pointed ones, scratching the backs of pull reeds. No matter how gently I used the file, the reed would open, and even a hair makes a difference in it's air consumption. I used to think upened up reeds made it louder, but they start guzzling gas. Resetting the reed poses a problem. You can push back into position, tune it, and the next day it's back out of tune. Noticed that pushing the reed back in place, always flattens the note.