If you have sufficient computing resource and great patience, you could finish the simulations of all kinds of perovskites. The perovsiktes is a family of compounds with rich varieties including crystal structure, components, stochemistry, conductivity and so on. The most important thing is to do something interesting.
If the crystal structure is too large, the device simulation would become quite heavy. You need huge computing resource.
The simulation of a nonstoichiometric compound is challenging. There is no easy way to simulate the compound you mentioned. You may simply consider some of the ordered structures to compare the total energies of them and to find out the lowest one.
