I have a snake who's just a little bit bigger than yours (56g) and he's tackling fuzzies like no tomorrow. If he's eating that many pinkies, fuzzies should be no problem. Corns are not like pythons. Corns can stretch a little and be okay. While pythons should be fed something smaller or the same size as their largest girth, corns can easily eat something larger. I'd use the 10-15% rule as has been suggested. If your little one is 49g, I'd feed him something around 5-6g.