Effective mass is different than the actual "weight" of an arm. The following site will be a big help: (http://www.gcaudio.com/resources/howtos/tonearmcartridge.html) It should answer most(if not all) of your questions.
Cartridge compliance vs tonearm effective mass
Hello, i have some difficulty grasping the relationship between those items. On the scale, what is considered "high" and "low" compliance. Typically, a low compliance cartridge need a heavy arm. Consequently, a high compliance cartridge need a lightweigh arm. I currently have a Benz Ruby 2H (compliance of 15) mounted on a SME V with an effective mass of 10/11gram. My question is: how do you properly match cartridge to arm using compliance and effective mass of tonearm. I am considering replacing my Benz Ruby 2H with a Benz LP or a Koetsu Jade/Onyx Platinum, or Lyra Titan or VDH Condor. Which would mate best with the V and which should i absolutely avoid. 70% of my listening is Jazz. HELP!!!