In this study, we address challenges in designing quantum information processors based on electron spin qubits in electrostatically-defined quantum dotsQuantum Dots (QDs). Numerical calculations of charge stability diagrams are presented for a realistic double QD device geometry. These methods generalize to linear QD arrays, and are based on determining the effective parameters of a Hubbard modelHubbard Model Hamiltonian that is then diagonalized to find the many-electron ground state energy. These calculations enable the identification of gate voltage ranges that maintain desired charge states during qubit manipulation, and also account for electrical cross-talk between QDs. As a result, the methods presented here promise to be a valuable tool for developing scalable spin qubit quantum processors.