Well, I was going by the original post where you’re rotationally symmetric, not mirror-symmetric. But for mirror symmetry, pick the mirror plane to be the z direction, then you just make your spins either both +z or both -z.
Well, I was going by the original post where you’re rotationally symmetric, not mirror-symmetric. But for mirror symmetry, pick the mirror plane to be the z direction, then you just make your spins either both +z or both -z.