If I had any sense I would stay out of this---but today I seem to be adequately senseless
My way of adjusting them was to loosen the three screws and turn (while cold) the body (CCW?) enough to just close the choke plate. Although I do not see it on yours, I believe they had a reference arrow molded into them that served as a reference and the nominal setting lined up with a marking on the die cast part of the housing.
I'll end my possible embarrassment there
"A pessimist sees the difficulty in every opportunity, an optimist sees the opportunity in every difficulty” ---Sir Winston Churchill
"Political extremism involves two prime ingredients: an excessively simple diagnosis of the world's ills, and a conviction that there are identifiable villains back of it all." ---John W. Gardner
“You can’t go back and change the beginning, but you can start where you are and change the ending.” ---C. S. Lewis