Setting final dimensions while protecting against the possibility of merging shapes is provided by performing a decomposition of tolerance bands onto a plurality of masks for use in a multi-exposure process. This allows the maximum process latitude between open and short failure mechanisms, while also providing a mechanism to enforce strict CD tolerances in critical regions of a circuit. The decomposition enables co-optimizing various types of shapes placed onto each mask along with the source used to print each mask. Once the tolerance bands are decomposed onto the two or more masks, standard tolerance-band-based data preparation methodologies can be employed to create the final mask shapes.