Despite of being one of the most widespread green energy sources, the efficiency of PV rooftop installations is still repressed by shading and by the absence of a rigorous irradiance-aware placement approach. The goal of this work is to reach optimal energy production via an irregular placement of PV modules, by considering two degrees of freedom: orientation of each PV module and topology. Experimental results will prove the effectiveness of the proposed solution onto two real world case studies, with an increase of power production of up to 40%.