Because distance overestimations exist in the standard VFZ framework, use of ensembled VFZ-GBO interpolation or data augmentation may be necessary to mitigate discontinuity artifacts when crossing the exterior of a VFZ as discussed in Section 2.1. Alternatively, the "excess" points in a gridded sampling can act as a type of data augmentation and help to address this issue. We plan to explore these topics in future work. Section S4 contains further discussion of a gridded sampling approach.