Slightly high nut on UV777, file?

[Random Hero]

Hey guys,

I think I have a slightly high nut on my UV777. It's the older 1 piece neck version if this helps. I checked under the locking nut and there are no shims, so I presume it's gonna need filing? What size file do I need for this job?

At present I have the action around 0.8-0.9mm at the 12th fret, which I guess is considered low, but I would presume I could bring the bridge up slightly for more pull up should I lower the nut a little, right?

Any help would be great.