Originally Posted by
Simon Barden
As Waz says, there's no real difference. Most factory-cut nuts have lightly oversized nuts anyway, you don't want the slots too tight otherwise the strings stick and you get tuning issues.
The only real issues you may have is when increasing the string gauge, especially if you've cut the slots yourself to closely match your standard preferred string set. But even then, you can probably cure any tightness with a bit of fine grit paper.
My electric guitars have a mixture of D'Addario .009" sets (9-42) and .0010" sets (10-46) on them, though I'm moving them all to 10s as time goes by. Once you get used to 10s, 9s just feel too sloppy. But string bending does get harder and whilst your fingers will compensate over time, I know that some big bends take an effort, so I don't see myself ever going up to 11s (unless I ever decide to downtune).