It is much better to use g (the capital G is not the correct unit) as a unit for centrifugation steps, which refers to the acceleration applied to your samples (so 10,000 g means 10,000 times Earth's gravitational force). Also, 'g' is the symbol written for 'RCF' values.
RPM (revolutions per minute) is not as useful a unit, because the force varies with the radius of your machine (the bigger the radius, the more acceleration is applied to your samples for the same RPM).
Using g, you can easily replicate experiments.
The formula about these two variables is as below:
Souce: NovoPro 2018-02-07