A statistical model describing the polymerization of branched ethylene homopolymers from a single site catalyst (Macromolecules 2002, 35, 2514) for continuous stirred-tank reactor (CSTR) is extended to the case of a mixture of single-site catalysts in order to establish qualitative criteria to optimize the processability of branched metallocene ethylene homopolymers. Monte Carlo simulations are used for combinations of two metallocene catalysts, and an analytical solution is proposed to predict the ternary diagram of segmental composition (linear chains/free arms/inner backbones) and the molecular weight distribution for any combination of single-site catalysts. It is shown that the optimization of shear and extensional properties requires good control of the extent of vinyl termination and of the size of the segments between branch points.