Generally they are active in the middle of the night, as you saw -- mine typically not before 1 AM or so, though sometimes earlier. As far as time to acclimate, you will hear all kinds of answers, from handle them right away to never handle them except to clean cage, etc., but I think if you want to interact with them and get them used to you, you need to strike a balance between letting them get comfortable in their new environment and stressing them all over again if you suddenly start handling them out of the blue weeks after they arrive. Different snakes will have different personalities and some will never seem to have a problem with handling while others will never seem to get used to it.