Tweaking the new Grado Timbre Sonata 3

Sonata 3 Timbre Series
Recommended Load Range: 10k - 47k ohms

But the highs are a bit more extended... , which seems to be a bit excessive, but just a bit, almost, but not quite sibilant.

Use 10k Ohm instead of 47k Ohm if you think there are too much highs

Grado MI cartridges are not sensitive to capacitance (associated normally with different phono cables / or if there is a capacitance switches on the phono stage), but load resistors is another story and the manufacturer gave you a range from 10k to 47k for this particular model, this is cartridge loading. The cartridge is MI, so what you see is different loading for MI, not for MC cartridges. 

  

Very few manufacturers of the phono stages will give you optional load for MM/MI, for this reason I am using JLTi Phono stage with special mod made by the manufacturer for me. I can use whatever resistors (RCA plug- in parallel) for my MM or MC cartridges, because internal load resistors in my JLTi is 500 000 Ohm, for my MM or MI i can use whatever up to 100 000 Ohm (100k Ohm).

For all my MM/MI I’m using 47k - 100k Ohm.

But if i want to load it i can do that to 10k or whatever.

Apart from Grado the OP is referring to, I have never seen any other cartridge with recommended load resistors range from 10k to 47k given by the manufacturer.

But very often the recommended range is 30k - 100k Ohm for MM.

The 47k Ohm is not mandatory for MM or MI cartridges and never was!