Based on Part I's (47) horseradish peroxidase (HRP) experiments on rats, this paper proposes a new, two-dimensional convection-diffusion model for macromolecular transport in heart valves. Experiments require two valvular intimae, one underneath each endothelium. Tompkins et al. (34) found large variations in shape and magnitude in transvalvular ¹²⁵I-LDL profiles from identical experiments on four squirrel monkeys. Their one-dimensional, uniform-medium diffusion-only model fit three parameters independently for each profile; data variability resulted in large parameter spreads. Our theory aims to explain their data using one parameter set. It uses measured parameters, some aortic values, but fits the endothelial mass-transfer-coefficient (k_a = k_v = 1.63 x 10^-8cm/s) and middle layer permeability (Kp₂ = 2.28 x 10^-16 cm²) and LDL diffusion-coefficient (D₂(LDL) = 5.93 x 10^-9cm²/s) using one of Tompkins' profiles, and fixes them throughout. It accurately predicts Part I's rapid localized HRP leakage spot growth rate in rat leaflets that results from the intimae's much sparser structure, dictating its far larger transport parameters (Kp₁ = 1.10 x 10-12 cm², D₁(LDL/HRP) = 1.02/4.09 x 10^-7cm²/s), than the middle layer. This contrasts with large arteries with similarly large HRP spots, since the valve has no internal elastic lamina. The model quantitatively explains all of Tompkins's monkey profiles with these same parameters. Different numbers and locations of isolated macromolecular leaks on both aspects and different section-leak(s) distances yield all profiles.