As mentioned before upon maturity scorpions no longer moult. All desert hairy scorpions in the hobby are WC, and alot of them are adult males (males go out hunting females, get hunted themselves by people out looking for them).
Regarding moisture, they do better with an inch or so under their 6-8inches of sand, with a tube leading in to it, once a month you can add a small ammount of water. Its a more natural way of providing moisture, as they'll burrow to their humidity and moisture requirements. That said, timing adding water with the addition of a small water bowl wouldn't hurt.