  ITER coil tolerances are re-evaluated using the modern understanding of
coupling to least-stable plasma modes and an updated center-line-traced model
of ITER's coil windings. This reassessment finds the tolerances to be
conservative through a statistical, linear study of $n=1$ error fields (EFs)
due to tilted, shifted misplacements and nominal windings of central solenoid
and poloidal field coils within tolerance. We also show that a model-based
correction scheme remains effective even when metrology quality is sub-optimal,
and compare this to projected empirical correction schemes. We begin with an
analysis of the necessity of error field correction (EFC) for daily operation
in ITER using scaling laws for the EF penetration threshold. We then consider
the predictability of EF dominant mode overlap across early planned ITER
scenarios and, as measuring EFs in high power scenarios can pose risks to the
device, the potential for extrapolation to the ITER Baseline Scenario (IBS). We
find that carefully designing a scenario matching currents proportionally to
those of the IBS is far more important than plasma shape or profiles in
accurately measuring an optimal correction current set.
