So vdH is making the calculation for you in recommending a tonearm with 14g effective mass. That should not be taken as a firm directive. 12 to 16g would be fine. Note that effective mass should include the weight of the headshell, the cartridge itself, and the screws/nuts that hold the cartridge in the headshell. Most tonearm effective mass specs will include the mass of the OEM headshell. Since all those other items are out on the end of the lever, they can pretty much be added to the mfg spec by simple arithmetic. If you use an aftermarket headshell that differs in weight from that of stock, just add or subtract accordingly, in grams. I've got to disagree with MC on the idea that "any" phono stage would be adequately driven by 0.65mV output. Just off the top of my head, I would say you need at least 55-60db gain. My main point is that a typical MM phono stage will not do the trick. Those typically supply 40 to 50db, max.