Cartrodge break-in and counterweight question?

Recently, I purchased a Denon DL-103R. I had read so many good things about this cartridge, I just had to try it!
This is a low output moving coil, so before I pass any judgement on it, how long should it take for this cartridge to break-in?
Also, when I mounted the cartridge in the tone arm, I had to position the counterweight nearly at the very back of the tonearm. Would it help sonically, if I ordered a heavier counterweight?
In advance, thanks for your input.