Derived planet-to-star radius ratios (R _p /R _⋆) vs. aperture size from fitting WIRC photometry with various sets of detrending covariates. Error bars indicate 1σ uncertainties. Vertical shading highlights the aperture size that minimized the rms scatter as described in Section 3.1. In addition to the covariates listed in the legend, all light curves are detrended by time.