A novel approach to robust nominal and tolerance circuit design is presented in this paper. The objective of the paper is to provide a methodological support for robust design in cases where a choice among different projects for a given circuit is needed. The case study considered concerns the optimization of the feedback control circuit of a voltage-mode regulated DC-DC converter. Six different project approaches are adopted to generate a set of optimal feasible project solutions by means of a joint Monte-Carlo/interval-analysis numerical method, according to control loop performance constraints and using commercial values and tolerances of circuit parameters. The search for the optimal feasible projects is performed with different design priorities, like minimum sensitivity of dynamic performances, maximum tolerance of designed parameters, maximum centrality of the performance indexes within the allowed tolerance range. The results presented in the paper highlight that, given a set of design constraints, the best projects fulfilling the selected priority are provided and a comparative evaluation of the robustness of different possible solution for the same design goal is allowed.