Resonator feedback resistor for 50MHz, 3.3V?

Phil Pilgrim (PhiPi)

I'm working on an SX board that has to run at 50MHz on both 5V and 3.3V Vdd. I'm using the recommended 10K feedback resistor in parallel with the 50MHz ceramic resonator, but I'm wondering if this is optimal for both voltages or just 5V. If just 5V what might a good compromise value be?

Thanks,
-Phil