1+ on TD's post.

FWIW I would put the strings on, and do a full set up (set the truss rod and the action) before doing anything else. Only shim or sand if you have to.

If it comes to that, you can put a veneer shim on the two holes on the nut side of the pocket to adjust the angle. Simpler than sanding ;-)

But I don't think it'll come to that.