Analytical estimates for the power spectra of the largest low-L mean-fields at 143 GHz. The various components are discussed in more detail in Sect. C.1 (mask), Sect. C.2 (noise), and Sect. C.3 (beams). The mean-fields all couple most strongly to even modes of the lens reconstruction, due to the approximate north/south symmetry of the scan strategy and Galactic mask.