Interesting, that would support why my searches came up empty. I am a huge fan of weight reduction, especially rotational, and I am hoping someone can help me out.
It's a common misconception that lighter equals better. Rotational inertia and mass moment of inertia are two different issues. More important is the inertia and NOT the weight. I had to demonstrate this to a sprint car team with a steel driveshaft that weighed more than their hella expensive titanium one but spun up a lot quicker. It's also cost chump change.
Equations for inertia are easy to find. Oversimplified, the distance the mass is from the axis (radius) is much more critical.