i would seriously reconsider keeping them. i've kept rough greens which i've heard are almost exactly the same as the smooth greens. they're very hard to get eating, i went through 4 of them before i got 1 that ate. i know, i'm a sadist, but i was determined to keep them as i heard it could be done. they would hide under cork bark a lot (didn't display well) and were very nervous. the only one that i saw eat was eating gut loaded crickets and mealies. it lived about 2 or 3 years.
if you want a real nice display snake, put a little more money out and get a tree boa/python (they eat rodents). they're almost always mean as hell but are perched in a tree for you to see almost all day. amazon tree boas hide a little but the green tree python and emerald tree boas don't hide much, if at all.
i've had/have a lot of snakes and these green snakes were the biggest pain in the ass out of all of them. you might want to try "cyclophiops major" if you can find them. they hide as well but readily eat worms (a TON of worms, be prepared $$$). you keep them the same way you would a garter.
there's a lot of easier cool snakes out there if you're not hell bent on a green one or bug eater. hope i helped, good luck.
that's c. major below, not mine but i did have one and sold it.
daaamn $47! they're usually $10-$20. anyway, make sure you see it eat with your own eyes, don't take anyone's word for it. people will say it's eating because the crickets are gone, but they're probably hidden in the substrate or escaped.