End of the night update: Got card facing direction working. It was broken for a looong time before I stopped to wonder if the math I was doing was wrong instead of the implementation. Turns out, I was calculating dot(world_space_normal, world_space_camera_forward) to determine which side of the card to show. Should have been dot(world_space_normal, vertex_towards_camera).
(also, as far as opening Euchre hands go, not the greatest :lol_sobbing: )