The right way to do this is to disconnect the Pitman arm, intermediate shaft, and return line, and drain the gear. If I remember right, the spec is 15 inch lbs (rotating) higher on center than 45 deg off center. It's so little that you can't even feel it if you turn the steering wheel, though you can if you turn the input shaft with your thumb and forefinger.
It MAY not remove the play. If it doesn't, you need a reman gear. It means the sector shaft and/or piston teeth are worn to the wrong shape.
If you adjust it to remove the play, you are VERY likely to overtighten it. Which makes the vehicle quite difficult to control (no return to center), and will wear out the gear very quickly. If the PO messed with the adjuster, this is probably the situation you're already in.