Variation in the Fourier parameters of BL Her models (displayed in yellow) in the G band computed using the convection parameter set C as a function of stellar mass and period. Low mass models indicate models with M ≤ 0.6 M_⊙. The grey shaded regions in the lowermost panels highlight that while low-mass models may suffice to model BL Her stars in the Magellanic Clouds (sub-plots c, d), higher mass models may be needed to reliably model BL Her stars in the All Sky region (sub-plots a, b).