People can just submit a forms saying they want their pastel to be compared with other pastels, and have the people at the expo vote for who they think has the best one =p. The snake can stay at the owner's booth on display, and the people will be told where they can find these contestants! I walk around the expos anyways. When you see one, you can write it down or they can supply you with a form =p. That way you vote for it on the form, then submit it at the end! There's tons of little raffles, and I think this could just be one more little fun side-event that goes on at the expos ^_^
There doesn't even need to be a "standard". People will vote for what they like, and the snake with the most votes will be considered the best example AT THE EXPO. Not worldwide.. LOL