Nut height

Hi, everbody

I´d like to know about you guys who use 0.9 strings gauge , how much in milimeters is the best height of the strings over the first fret, because my luthier move it, and it was perfect ...they love to do this ...

The neck is ok with a little relief, but the little E is buzz arount the 7th fret when doing bends, zzzz

Thanks, Paulo