Clearaudio Clarify Help Needed!

I am in the process of setting up the Clearaudio Ovation turntable with Clarify tonearm I purchased used. All good until came time to move the counterweight to adjust cartridge downforce.

The counterweight will not move. The tt manual is a piece of crap, lacking information and offering only a few lousy photos. It states "By loosen the screw on the counterweight on the tonearm-tube you can adjust the tracking force of your cartridge by moving the counterweight (shown in the picture below)." The picture shows the counterweight (CW) on the tonearm tube with a red arrow pointing in one direction and a green arrow in the other. There is no indication of where the "screw on the counterweight" is located. I have located a very tiny set screw on the underside of the counterweight, but don't have an allen wrench tiny enough, long enough to reach it. Could this be the "screw on the counterweight" I can "loosen"? It is only accessible if I remove the tonearm - which would make balancing the arm very difficult, as after balancing it I would have to remove it again to tighten the screw? Why would Clearaudio have buried the set screw on the bottom of the counterweight, where inaccessible without removing arm?

There is a knob on the back end of the tonearm. Is this the "screw" I'm supposed to "loosen" to free my tonearm? I turned it both directions but it had no effect on the freedom of the counterweight. It appears to connect to a long spring that runs the length of the tonearm? What is the purpose of this knob? How am I to know when it is properly turned to proper position? Why is there no mention of it in the "user manual"?

Any help much appreciated!

Balthus