Hi, Jim,
To really get a sense of the effect of resistance loading on a LOMC cartridge, try the extremes, and the (available) increments between them. You'll find that the optimal loading for your system becomes clear. The trick is to listen to a variety of music at each setting. Take some time to listen for impressions of the overall sound, and the nuances of tonal balance, soundstage, articulation, etc.; unless it sounds awful, then quickly move on. '-)
Regards,
Tom