You would get better water washout resistance with a #1 and improved (over an MPG) friction by using a lower base oil viscosity.
As I've said before, bearing speed is more than RPM. Bearing size must also be considered in determing if a bearing is really operating at high speed. Any idea what the ID (bore), OD, width, RPM and operating temperature is? ID (d), OD (D) and width (B) can be obtained if you know the bearing model number. With bearing parameters and RPM you can calulate the speed factor DN or NDm (better).
What thickener are you considering?