How to add a reticle to a two camera (left/right eye) setup

I have a two camera setup for my VR scene. This allows me to have two 360 mapped spheres, one for the left and right eye, so that I have stereoscopic 360. This works really great, but now I need to add hotspots and also include a way to interact with them.

My question is this, how can I add a reticle to my camera now that I have split the camera up into left and right? I tried adding a sphere to the Left eye camera, and put it on the UI layer so it would not be culled by either of the cameras. This works, in so far that I can ‘see’ the sphere in both eyes as I move my head around. But I get a huge shift in the position of the sphere between eyes. The effect is that I get horrible double vision when looking at the sphere.

I think I may have to add the reticle object outside of the camera and then move its position to the camera on every frame.

Any other ideas?

Were you able to solve this issue ?