Illustrative compositions at maximum light for some of the models used in this study. With the exception of helium, mass fractions of all elements are taken directly from the Fink et al. (2014) and Kromer et al. (2015) deflagration models. Helium abundances are shown as dashed horizontal lines. As these pure deflagration models predict fully mixed ejecta, we have chosen to maintain uniform helium abundances throughout.