Hmm, you might be correct that it's the "green" screw to the left of the head, the one on the right looks like it's for adjusting the tape guide....
Problem is that if you accidently pick the screw for height adjustement or tape guide, these settings can't be restored "by ear" once they've been changed....need calibration tapes to get them back.
What are you trying to transfer? Precious tapes? If not, you might want to mark the current settings of the screw and see/hear what it does when turning them, but better find someone who has done azimuth adj. on these decks before and ask them or call a Nak technician. There are still a few left.