Reaction wheel assemblies having relatively compact and lightweight form factors (referred to as “small scale” RWAs) are disclosed. Such small scale RWAs are well-suited for deployment onboard relatively small satellites, but are not restricted to usage within any particular device or platform. In one embodiment, the small scale RWA includes a primary support platform to which a rotor is coupled for rotation about a spin axis. An axially-expanded face-to-face (DF) duplex bearing pair is disposed between the rotor shaft and the support platform. The DF duplex bearing pair includes first and second rolling element bearings positioned around an intermediate portion of the rotor shaft. The first and second rolling element bearings have first and second bearing load lines, respectively, which are spaced by a tailored bearing load line separation (SLL).