  We continue the investigation of how to use the divergence-free condition to
resolve the azimuthal ambiguity present in vector magnetogram data. In previous
articles, by Crouch, Barnes, and Leka (Solar Physics, 260, 271, 2009) and
Crouch (Solar Physics, 282, 107, 2013), all methods used an expression for the
divergence of the magnetic field that involves differentiation of quantities
that depend on the choice of azimuthal angle. As a result, all heights used to
approximate line-of-sight derivatives should generally be disambiguated
simultaneously. In this article, we investigate a set of methods that use an
expression for the divergence that involves differentiation of quantities that
do not depend on the choice of azimuthal angle. This results in an expression
for the divergence that can be used to disambiguate each height independently.
We test two methods using synthetic and find that the two-step, hybrid method,
adapted to disambiguate each height independently, generally produces
reasonable results. Moreover, the time required to compute solutions is
substantially decreased in comparison to the corresponding method that
disambiguates all relevant heights simultaneously.
