Mike, I have always treated mine as I would the more xeric Tills. I do know that most of the cultural requirements call for high light and good moisture to induce flowering but for some reason I've always placed them in the "hard-leaf, low water" category. I figure any plant that's tough enough like it (my wife accidentally backed over a clump of the small form with her car) doesn't need all that moisture.
P.S. The clump sure got beat up but came roaring right back after a couple of years.

Thanks Gonzer. Yes, from just looking at it, I would think diaguitensis would be both a xeric, and hearty. It has pretty hard leaves. Mine's not doing that badly, I just noticed a hint of brown at some of the leaf tips and wondered about it.
Thanks!

Mike