We present a two-dimensional study of low-loss photonic crystal defect waveguides built from a III-V type semiconductor-based system surrounded by cylindrical air pillars in a prototypical lattice. Varying the parameters of the lattice, including several taper geometries and lengths in the typical wavelengths usually employed in telecommunications, we perform an extensive statistical survey that determines a parameter map that can be taken as a guide by transmission hardware designers to choose the best lattice geometry in terms of optimum transmittance and minimization of the impedance mismatch.