  The neutron total cross sections $\sigma_{tot}$ of $^{16,18}$O, $^{58,64}$Ni,
$^{103}$Rh, and $^{112,124}$Sn have been measured at the Los Alamos Neutron
Science Center (LANSCE) from low to intermediate energies (3 $\leq E_{lab}
\leq$ 450 MeV) by leveraging waveform-digitizer technology. The $\sigma_{tot}$
relative differences between isotopes are presented, revealing additional
information about the isovector components needed for an accurate optical-model
description away from stability. Digitizer-enabled $\sigma_{tot}$-measurement
techniques are discussed and a series of uncertainty-quantified dispersive
optical model (DOM) analyses using these new data is presented, validating the
use of the DOM for modeling light systems ($^{16,18}$O) and systems with open
neutron shells ($^{58,64}$Ni and $^{112,124}$Sn). The valence-nucleon
spectroscopic factors extracted for each isotope reaffirm the usefulness of
high-energy proton reaction cross sections for characterizing depletion from
the mean-field expectation.
