How to get chat bubble height?

You probably already know that the new bubble chat somehow always stays above your head, even when playing animations.

This is something i need for my nametag gui.

I already tried getting BoundingBox Y size, but when walking and looking around the box rotates, so the position is not exact.
I also tried raycasting down to the humanoid root part, but the results were not exact either, and for some reason the casting direction needed to be 10000 studs down or it wont work.

Does anyone know exactly how bubble chat determines height?