Since the frets of my SG are a little bowed, when I misure the action, I've to do it between the height of THE OUTER EDGE of the fret and the lower part of the string, or between the point where the string actually touches the fret (which is 1/2mm higher due to the bowed frets) and the string? Thank you very much for the help!
To the point where they touch the frets when pressed vertically downward.

Not sure what you mean by 'bowed' frets. The frets should normally follow the natural radius of the fretboard
'It takes 100 guitar players to change a light. One to change the light and 99 to stand around pointing, saying..."Yeah man, look...I can do that too"...'

My gear is in my Profile

Builds & Refurbs
Hondo 780 Deluxe
Gibson Studio
Epi LP100
yeah, I mean exactly that! just I'm italian and I didn't know exactly how to say it xD.... thanks!!!