I think Doug that your question might be more related than you give yourself credit for, simply because (I suspect) Ortofon would normally intend that their LO MC be used with their own step-up tranny (not a necessity with the Pass phonostage). I would second Tom's advice in principle, but having said that would also add that auditioning at home is free except for your time, and that David shouldn't pass up the opportunity for a bit of 'ear-education' by going ahead and listening to the results with a small variety of loading options chosen at strategically placed intervals. As a rough suggestion, I would try the lowest setting, then double that, and double that, and so on for a few to several iterations, depending on how low the lowest possible setting is. Listen not only for natural frequency response (not constricted, not overhyped), but also for good tradeoffs of image focus vs. image size, bass definition and tautness vs. bass openness and weight, and unfettered dynamics vs. transient and decay cleanliness. The 'sweet spot' of the loading range that you find will not only have much to do with the electrical properties of your cartridge and phonostage, but also your total system and room response and set-up, not to mention personal preferences. Try it, it's fun! :-)