Providing a usable domestic brain-computer interface (BCI) for persons with disabilities requires that the development team ensure ease of interaction for all the potential users. To do this for individuals with complex needs often requires that an approach is tailored to a specific user. However, in developing a domestic BCI it is necessary to consider the provision of an application which hides the complexity of the underlying science from the user whilst delivering acceptable levels of interaction for many. This is not an unusual circumstance in the realm of assistive technology. We present a cohesive test suite which allows the development team to assess what constitutes an acceptable level of accuracy in a four-way command interface using steady-state visually evoked potentials (SSVEP). It also facilitates a uniform assessment of the level of accuracy achieved by a specific user operating a BCI and provides a means of contrasting and selecting performance parameters in order to enhance user performance.