Clock networks constructed with variable drive strength clock drivers are prepared for tuning. The clock drivers are built from a smaller set of base standard cells. Locations of the input and output netlists of the macrocells are marked and reserved even through the extraction process. The macrocells are able to be flattened, generating a netlist with the base cells, and recombined during circuit simulation, thereby reducing the number of iterations, making the tuning flow more efficient. The clock network is initially tuned by adding or removing cross-links in the mesh to balance capacitive loads on each driver of the clock mesh.