These guys vary in size due to location and species (how much of which is still up for debate). Generaly speaking, one around the 2" mark is getting up there.
They don't seem to be huge burrowers, so I generaly give them about an inch of play sand (you wet it thoroughly, put it in the bottom of the enclosure, and let it dry thoroughly), a small, shallow water dish and a hide of some sort. I keep them in small sized critter keepers, which I managed to get at the local dollar store.
This genus is known to have fairly potent venom, so I would recommend a great deal of caution when dealing with them. Use instruments to move them and never free-handle them.
I have been doing a little bit of research on them as well, but can't seem to dig up much dirt on the ones you are specifically speaking of. Currently I keep H. trilineatus and H. hottentotta. I am seeking a scientific name for it. Perhaps someone here has one which they may have already turned up something through research on? East African Devil Scorpion... said to be reaching near three inches by most of the current sellers. There are no Hottentotta genus scorpions with relatively similar coloration on Jan's site, nor any others I have come across who have scientific names posted.
I do believe if anyone wants info on this scorp they are not gonna find it by researching any species of Hottentotta. It's NOT a Hottentotta scorpion!!! It is actually a Babycurus, possibly a Tityus (at least some of what has been brought in under this title is, though some others are actually H. trilineatus or polystictus as found at one shop in North Carolina). Take another look at the aculeus. Note the subaculear spine. A feature only found in Babycurus and Tityus scorpions (that I have seen). I can't believe I looked right by it. An no, this is not seen in Hottentotta. As I currently keep two confirmed species of Hottentotta. Exact species is unknown by me, but I'll know shortly after mine arrive.