Recommend cartridge for pass labs preamp amp and Harbeth 40.2

Michael, i think it's not correct to recommend a cartridge for certain speakers of even for certain phono stages. I'm sure Pass is great (i use his gear myself) and designed for a wide range of cartridges. 

Cartridge for tonearm make sense. But having different cartridges makes more sense if you're still searching for your type of sound in your system. 
Different type of cartridges MC or MM or MI ... Different design, diamond profiles, different cantilevers.... you never know what you prefer until you will try it by yourself. 

Higher load is actually unload, try 47k Ohm for your MC, try Vishay Naked Foil Audio Resistors by Texas Components for direct replacement in your phono stage, these are the best audio resistors, will help you a lot with transparancy you're looking for.