Phonostage A with 100Ω hasn't the same sonic result like Phonostage B
with 100Ω. It is a endless discussion, best you can do, try your setting
and what you like best, that's it. When you buy a new Phonocable, you can roll
the dice again.
The better your Phonostage is, the higher you can go (1kΩ-47kΩ),
less loading, less coloration (when you step down from 1k to 300, 200, 100 ...-
-> the higher frequencies are more and more dampened, sound gets slow and
dull but a lot of Preamps deliver a listenable result that way :-)
The majority of Phonostages are not listenable above 1kΩ, but this isn't a
technical fact, it is the limited knowledge of Designers to get a proper solution.
That's the reason for the recommendation: 100Ω - 47kΩ
(That means: it doesn't matter what you have, thank you for buying our
cartridge)