Cartridge Loading

Well, Halcro, you know, the most important from all, is, that the cartridge fits to the tonearm.
Next is, copying something from a manufacturer is nice but more or less without any worth.Every one has his own religion. A horrible sounding preamp does not get any better with any load, one of the reasons, why these discussions are always endless.
Next, 100 ohms from Preamp A are not identical to 100 ohms from Preamp B.
That's one reason why there are so many different sounding units are out there.
Ernst Benz made all cartridges for 47kohms. Later the manuals were changed to 10-47kohms, it makes the sale much easier and the Dealer can say "yes" to everything the customer has at home.
Best is always to try with the given Preamp, when that one will be replaced the game starts again.
And you need a Turntable which can show the real difference, not a colored result based on its construction.
Happy Listening.

Short:
47 kohm when you have a preamp which can do it without sounding thin, dead and analytical
1kohm when you have a normal preamp
below 200ohms when you have a very analytical and harsh sounding high end System and you want to soften it.
or
MM Phono and a matching high quality Step Up.