I would start off by loosening the stator fixings and seeing if it can be re-centered to give clearance all round. It may be possible to ease the mounting holes slightly.
'Easing' is a bit of a euphemism I'm afraid. I wouldn't go drastically enlarging all the holes but if a gentle caress with a round file were enough to centre it, perhaps by removing any burrs then I would give it a go.
That sounds better than the old brass shim as you can get a milk carton about anywhere. That's another goood and inexpensive idea.