Im pretty sure most if not all strains will perform well in hempy. In fact from what i can tell hempy is a replication of the earths ground. If you dig deep enough into the earth you will hit water. Although the majority of plants wont reach these pockets of water, the ones that do thrive (large trees etc). A hempy is the same concept.
Regardless, as long as the strain you pick comes from good genetics, i wouldnt worry. Just do some research and,find,a,strain that suits your needs. Check out tga seeds