Ambipolar conductance in graphene field-effect transistors (GFETs), and in particular their quasi-quadratic I-V transfer characteristic, makes these devices excellent candidates for exploiting subharmonic mixing at high frequencies. Several realizations have already demonstrated the ability of GFETs to compete with, or even improve, state-of-the-art mixers based on traditional technologies. Nonetheless, a systematic analysis of the influence on performance of both circuit design and technological aspects has not been conducted yet. In this work, we present a comprehensive assessment of the conversion losses by means of applying radio-frequency circuit design techniques in terms of filtering and matching, along with the impact stemming from physical and geometric variations of a fabricated graphene technology.