Rosy boas are kept in a very similar manner as sand boas. Make sure the ventillation is good and don't leave them with water dishes large enough to soak in.. Rosies need to be dry, but the same applies to sand boas, so you shouldn't have any touble..Keep meal sizes small, especially with baby rosies.. They can't handle the large meals sand boas can.
I keep all Erycines on Beta or Alpha chip produced by Nepco. It's cheap and comes in big bags
http://www.nep-co.com/labindex.html