A method includes receiving input indicating at least two of: (a) a coefficient of first sensitivity of an optical particle sizer (OPS) to a real part of a complex refractive index (CRI); (b) a coefficient of second sensitivity of the OPS to an imaginary part of the CRI; (c) a coefficient of a degree of monotonicity between intensity and particle size; (d) a coefficient of a dynamic range of the OPS; or (e) a coefficient of a limit of detection (LOD) of the OPS; determining ratings for the OPS using the at least two of (a)-(e) and at least two of (i) the first sensitivity, (ii) the second sensitivity, (iii) the degree of monotonicity, (iv) the dynamic range, or (v) the LOD; identifying an angle that corresponds to a maximum or minimum rating; and providing an OPS having a detection angle that is within 5 degrees of the identified angle.