Do you have the proper kit to measure the beam pattern?
I could not find the numbers in the workshop manual but on my MGF I have labels that say 2 degrees dip but nothing on how much to the side the beam should go.
I suspect the actual setting is based on the actual suspension height of the car. Like you, I could find nothing on the web that quotes exact measurements.
EDIT: I found this link - it leads to a pdf. It is more complicated than I thought!