Likelihood function for the fundamental domain scale of a cubic torus derived from a simulation of a toroidal Universe with or 2χ_rec/L = 1.5. The results from the profile-likelihood analysis (pink, clear circles) closely match those from the full marginalized likelihood (black, filled circles). Overlaid are additional profile likelihoods demonstrating the effects of changing the mode count and composition. In order of increasing constraining power, they utilize 837 IQU modes (grey, long dashed), 1085 I modes (blue, dotted), 1085 IQU modes (pink, clear circles), 2170 IQU modes (green, dot-dashed), and finally 1085 noiseless IQU modes (purple, dashed). Adding low-ℓ (ideally low-noise) polarization greatly increases the constraining power of the data.