Just found this advice on another forum, what do you think?

"Once in a while I encounter the same situation, particularly if I get the parts from AutoZone or Advance. Leave any anti-squeal feature in place or you'll be reminded that you removed them every time you hit the brakes. Best thing to do is to put each pad in a vise horizontally and carefully sand it down with a belt sander with a medium grit belt in it (parallel to the long dimension of the pad). That keeps it pretty flat and even. Don't forget to maintain a bevel on the leading edges of the pads. After doing this, everything fits. Next time, get your parts at someplace like NAPA and they'll fit the first time."