I'm setting up my new saddle's/action height, and I have two conflicting instruction's on which fret to measure the action from. Sweetwater says: Place the ruler on the 12th fret, making sure the ruler ticks are parallel to the string. Do this so that you’re getting an accurate measurement of the gap from the top of the fret to the bottom of the string. Fender says: Measure the distance between bottom of strings and top of the 17th fret. So which fret should I measure from?