Preamp cartridge settings

I have a preamp with the following available cartridge modes.

MM - Input impedance 47 kOhm, Gain 36,5dB
MC - Input impedance 100 Ohm, Gain 56,5dB
MC - Input impedance 220 Ohm, Gain 56,5dB

My cartridge, Ortofon X5-MC (was able to get another from Juki) has a recommended load impedance of 47 kOhm.

I currently have it at the 47 kOhm setting, and it sounds good, (I get distortion if I put it at the 100 Ohm MC setting...not tried it at 220 Ohm) but is there anything in that preamp setting other than the load impedance that is strictly for a MM cartridge?

I guess in general, are these types of settings, labeled MC or MM, more guidelines for most cartridges, and impedance load is what really matters? And high output MC cartridges kind of changed things?

Thanks!