Moon, for the most part, the size of their bankroll and info, and the speed in which both can be implemented.
There are only so many originators in terms of capping/moving the number, but there is a cottage industry of followers that are considered "wiseguys" in terms of play sides and size, when in fact they are merely "in the know"..imho.
Wiseguys operate in the flow of information whether they can cap a sport or not, they are networked, where some cappers/pro bettors primarily only win at their said specialty.
Walters is a networked wiseguy..Boston is a capper of a specific sport.