Ought we not to be applying the `applyLensing()` transformation here?  My rationale is explained in the docstring to the `galsim.Shear` class:
```
   Since we have defined a galsim.Shear as a transformation that preserves area, this means that it
    is not a precise description of what happens during the process of weak lensing.  The coordinate
    transformation that occurs during the actual weak lensing process is such that if a galaxy is
    sheared by some (gamma_1, gamma_2), and then sheared by (-gamma_1, -gamma_2), it will in the end
    return to its original shape, but will have changed in area due to the magnification, mu =
    1/((1.-kappa)**2 - (gamma_1**2 + gamma_2**2)), which is not equal to one for non-zero shear even
    for convergence kappa=0.  Application of a galsim.Shear using the applyShear method does not
    include this area change.  To properly incorporate the effective change in area due to shear, it
    is necessary to either (a) define the galsim.Shear object, use the applyShear() method, and
    separately use the applyMagnification method(), or (b) use the applyLensing() method that
    simultaneously magnifies and shears.
```