The CutCell method only generates a cubic hexa mesh with hanging nodes. The aspect ratio of the cells cannot be altered. If one wants to control aspect ratio of hexa elements, then the model should be pre-processed in order to take advantage of sweep mesh methods where possible. This will keep the cell count very efficient and give added control over the aspect ratio of cells. Note that this will incur extra effort to prepare the model geometry. As with every pre-processing stage for CFD, there is a balance between control over the mesh, and ease of mesh generation.