I have a sphere (but could be anything) that I am deforming over time and I want to have instances distributed on the surface. I've got it almost working except that I am getting unwanted spinning of some of the instances - See Blend File base of sphere and scrub around fame 100. In my setup I am aligning the euler to a single vector (the normal of the vertices) which works great for making the instances point outwards BUT recognise that without a second axis being defined there is nothing to prevent the instance spinning around on this vertex normal axis... which they are clearly doing. I assume that I need to define a second axis (X or Y) to prevent this unwanted spinning... but have no idea what vector to use and how to achieve it... and assume because it's deforming it's going to be harder to achieve?

The scene: Blender File

Internally Blender appears to be able to solve this as when I mute/disable the instancing in the geometry nodes (but keep the deformation node group) and then within the sphere's Object Properties >Instancing choose to instance on faces it works fine - no spinning of the instances. I recognise that this second approach is instancing on faces rather than vertices but the same issue arises in the geometry node setup if I choose to instance on faces (via points on faces and capturing the face normal).

Not sure if this affects any possible solution but I often want only a few instances, not one for every face on a sphere, and so actually cut a few faces from a sphere and use those (and then the remaining faces are used to spawn different instances in a separate object)

I want the power/flexibility of the geometry node setup as the Object Properties instancing is super basic... but definitely need to avoid the uncontrolled spinning. Can anyone help?