One thing I want to add. While hatchling balls are easier from a size standpoint, they can also be nippy and that freaks a lot of people out. They mistake it for aggression or anger, when it really comes down to the fact they are at the bottom of the food chain.
However, a well established ball at 6 months to a year old and around 600 grams or so, is usually calm, lazy and well mannered, very easy on a beginner with snakes and snake handling.
Gale