Cartridge loading of low output moving coils is almost of no consequence unless the preamp is unstable or unhappy with ultrasonic or Radio Frequency bursts at its input.
If you find that loading is making a difference with your setup, its an indication that the preamp has stability problems. This is because the cartridge is entirely unaffected by load at audio frequencies. You hear a difference because the load resistance is detuning the resonant circuit created by the cartridge inductance and the cable capacitance. So if the preamp is unaffected by this the loading will have no effect.
If you find that loading is making a difference with your setup, its an indication that the preamp has stability problems. This is because the cartridge is entirely unaffected by load at audio frequencies. You hear a difference because the load resistance is detuning the resonant circuit created by the cartridge inductance and the cable capacitance. So if the preamp is unaffected by this the loading will have no effect.