Question 1: The eff. mass is a product of the counterweight mass (plus the overall arm mass)and distance squared from the pivot point. So increasing the counterweight mass increases eff mass, yes. Increasing the counterweight mass and then moving it closer to the pivot in order to maintain the same VTF will reduce the eff mass.
Question 2: The tracking is affected by a number of factors, but just considering the natural frequency of the cartridge/tonearm system the location of the counterweight is only a part of the final result. The ideal range remains around 10Hz.
Question 2: The tracking is affected by a number of factors, but just considering the natural frequency of the cartridge/tonearm system the location of the counterweight is only a part of the final result. The ideal range remains around 10Hz.