How to place a Sphere on fingertips with OVRHand / OVRSkeleton?

I'm using Unity with Meta XR Tools for Meta Quest hand tracking, and I'm trying to create a hand-tracking based UI.

What I want to do:

When a finger pinch is detected, I want to highlight the corresponding fingertip.

I want to place a small Sphere on each fingertip and make it glow using Emission.

The Sphere should follow the fingertip movement.

What I'm struggling with:

I don't know where the Sphere should be placed in Unity.

I'm using OVRHand and OVRSkeleton, but I don't know how to correctly get the fingertip Transform.

I'm not sure whether the Sphere should be placed under the HandPrefab hierarchy or attached using OVRSkeleton bones.

The behavior I want:

For example, when thumb and index finger pinch, the Sphere on the index fingertip glows.

The Sphere should continuously follow the hand/finger movement.

In a Unity + Meta XR SDK environment, what is the standard or recommended way to implement this?