Line fluxes behavior for Herschel/HIFI lines 538.29 μm and 269.27 μm for different model series. First row left: dust-to-gas mass ratio, d/g. First row right: mixing parameter, α_set. Second row left: disk flaring, β. Second row right: maximum grain size a_max. Third row left: power law index of grain size distribution, a_pow. Third row right: strength of UV radiation field, χ_ISM. Bottom left: PAH abundance, f_PAH. Bottom right: disk gas mass, M_gas.