Variable angle of incidence spectroscopic ellipsometry (VASE) is commonly used for multilayer optical analysis, but in some cases this experiment (performed in reflection) does not provide sufficient information for the unique determination of the thicknesses and optical constants of the films in the given multilayer. We have found that augmenting the VASE data with data from other optical experiments greatly increases the amount of information which can be obtained for multilayers, particularly when they are deposited onto transparent substrates. In this work, we demonstrate the characterization of complex multilayer structures using combined reflection and transmission ellipsometry, ellipsometry through the substrate, and intensity transmission measurements. We also demonstrate the usefulness of dispersion parameterizations for the optical constants in the analysis of multilayers.