When I spoke to Peter Lederman about the SoundSmith cartridges his recommendation was a minimum loading of 470 ohms and preferably less (higher number). I subsequently acquired one of Bob Sattin’s Sky10 SUT that has a 1:10 ratio setting with 470 ohms or a 1:5 ratio setting with 1880 ohms. I don’t currently have a SoundSmith cartridge but employ the SUT with a Kiseki Purple Heart that has an output of 0.48mV and performs well on either setting into my MM (44db 47k ohm) input.
