Nice arm. Used it many moons ago with a Monster Alpha2.
From the manual:
Screw out the counterbalance thimble until the black ring is just visible. Fit the counterweight to the thimble and adjust until arm is balanced. Tighten the counterweight locking screw. Apply the tracking force by screwing in the counterweight/counterweight thimble. Once complete turn provides 0.25g tracking force with the standard counterweight.
(*1)Tracking Force Per turn
(*2)Recommended Cartridge Mass
(*3)Max. Range of Cartridge Mass
Standard Counterweight (provided with arm)
(*1)0.25g (*2)3-8g (*3)3-15g
Small Counterweight (*1)0.20g (*2)0-4g (*3)8-25g
Intermediate Counter (*1)0.30g (*2)8-13g (*3)8-25g
Large Counterweight (*1)0.40g (*2)12-20g (*3)12-30g