I would say that if your preamp linestage has about 20db or more gain, in addition to the 60db in your phonostage(for a total of 80db), you should be in the ballpark for a 0.21mv cartridge. If you have a low gain preamp, then you might need a step up device. Personally, I've found that a little more gain is desireable for me, and I like to have about 86db total gain in the phono and linestage for a cartridge that low in output. I think that around 85db total gain is a good figure for such a low output cartridge, and you can achieve that in a number of ways by combining the gains of the phono section, linestage, and possibly step up device, to arrive at about that figure.
IMHO, YMMV, and all that stuff.
IMHO, YMMV, and all that stuff.