If you believe that cartridge loading does not matter, well then, forget it and be happy.
Yes - I have a raft of highly regarded SUT's - and have experimented with a variety of top flight cartridges - from 3-40ohms internal impedance.
What I have found is that the "sound" and quality of the SUT dominates no matter what loading as long as the cartridge is not loaded down too far ( not less than 10x the impedance ).
In my view far more important is getting the gain right - finding the optimum gain for the phono stage/preamp so as you are not running the volume too low or too high.
Jonathan Carr has written on this forum - loading only really impacts the sound if there are issues with the ensuing phono stage. Loading does not change the "sound" of most modern moving coils. Therefore if a SUT presents 470ohms say to a low impedance cartridge, for example koetsu @ 3ohms, it doesn't really matter.
For those who hear a difference - there is a problem either with the phono stage or arm/cartridge issue.
For what its worth my reference system uses a current sensing MC step up into a tube phono stage, which I prefer to SUT's into same. Doesn't mean you can't get a great result with SUT's.