Sure, there are many variations to consider depending on your device details. The precise answer depends on the materials and which physical quantity you intend to measure in the lab.
For instance, for a double quantum dot, it is often useful to compute the lever arm matrix, which tells you how much a given gate bias affects the energy levels of a given dot. One may also be interested in quantities like the tunnel coupling between the dots to see if sufficient control may be achieved. Additionally, computing the charge stability diagram of a double quantum dot may be useful to determine if the single electron regime may be achieved with reasonable biases -- in addition, it can be useful to compute the confinement potential in such few-electron configurations to try to see if potential barriers are low enough to allow tunneling in principle.
In summary, there is a very long list of simulations one can do with QTCAD which are described in our tutorials. Without more detail on your structure, it is difficult to make specific suggestions.
