Eigenstates of the total spin can be used to intrinsically encode a direction, which can later be decoded by means of a quantum measurement. We study the optimal strategy that can be adopted if only product states of N-spins are available; these states are likely to be the only ones that play a role in practical applications. We find that the best states are those with minimal eigenvalue, i.e., with completely antiparallel spins. We also give a prescription for constructing finite measurements for general encoding eigenstates.