Timing-constrained power-driven gate sizing has aroused lot of research interest after the recent two discrete gate sizing contests organized by International Symposium on Physical Design. Since then, there are plenty of research papers published and new algorithms are proposed based on the ISPD 2013 contest formulation. However, almost all (new and old) papers in the literature ignore the details of how power-driven gate sizing fits in industrial physical synthesis flows, which limits their practical usage. This paper aims at filling this knowledge gap. We explain our approach to integrate a state-of-the-art Lagrangian Relaxation-based gate sizing into our actual physical synthesis framework, and explain the challenges and issues we observed from the point of view of VLSI design flows.