I find the MM input sounds better on the Steelhead in most instances. Anything at 0.25 or upwards and there’s plenty of gain. I’ve a 0.1 mv Audio Tekne that actually works on the MM input but there’s a little bit of noticeable background noise so I use a SUT.
But yes, I think the MM input sounds better and it’s worth looking for a cartridge with sufficient output to allow use on the MM.
Hana cartridges are a good match as are the Ortofon Cadenzas. I wasn’t thrilled with ZYX on the Steelhead, a bit lean sounding (Ultimate 100).
Sound Smith Zephyr is pretty good, the latest version. Plenty of flavors to choose from with the Steelhead as it’s very versatile and easy to use, with everything being on the front panel.