Half-light radii (open circles) and intensity-weighted mean radii (crosses) for θ₀ = 45°, T_out = 5 × 10³ K, and β = 0.1. BH masses are 10⁷M_⊙ (left panels) and 10⁹M_⊙ (right panels). Dimensionless mass accretion rates are ṁ = 1 (upper panels) and 100 (lower panels). Standard accretion disc predictions are plotted with redsolid lines, dotted lines show approximation , where R_d is the half-light radius of a standard accretion disc.