assuming you're growing your xerophytes on the south side. I'd say the scape will go in that direction away from the house. Have been growing agave and yucca in SE NC for over 20 years and can count on my fingers the number of times I've had an agave bloom. I wouldn't worry too much about that but haven't grown gracilipes. By the way, always plant your agave plants tilted to the south. It helps with drainage and increases the radiation in the winter.