  The rapid growth in size of quantum devices demands efficient ways to control
them, which is challenging for systems with thousands of qubits or more. Here,
we present a simple yet powerful solution: robust, site-dependent control of an
arbitrary number of qubits in parallel with only minimal local tunability of
the driving field. Inspired by recent experimental advances, we consider access
to only one of three constrained local control capabilities: local control of
either the phase or amplitude of the beam at each qubit, or individual Z
rotations. In each case, we devise parallelizable composite pulse sequences to
realize arbitrary single-qubit unitaries robust against quasistatic amplitude
and frequency fluctuations. Numerical demonstration shows that our approach
outperforms existing sequences such as BB1 and CORPSE in almost all regimes
considered, achieving average fidelity $>0.999$ under a decoherence rate $\sim
10^{-5}$, even with a few percent amplitude and frequency error. Our results
indicate that even for very large qubit ensembles, accurate, individual
manipulation can be achieved despite substantial control inhomogeneity.
