  The eikonal direct-reaction model, as used in spectroscopic studies of
intermediate-energy nucleon-removal reactions on light target nuclei, is
considered in the case of a proton target and applied to neutron removal from
$^{29}$Ne at 240 MeV/nucleon. The computed cross sections and their
sensitivities are compared using an earlier detailed analysis of carbon target
data. The nuclear structure input, for the $^{29}$Ne ground-state and $^{28}$Ne
final states, is that deduced from the carbon target analysis. The comparisons
quantify the sensitivity of the two reactions to the angular momenta and
binding energies of the active valence orbitals - showing the carbon target to
be relatively more efficient for removals from weakly-bound, low-$\ell$,
halo-like orbitals. Probing this sensitivity experimentally would provide
useful tests of these predictions and of the model's description of the
reaction mechanism.
