Read my post #57 on that.
Problem with the history of San Soo is that none of it can actually be traced to something. While Woo probably did have some training in kung fu and was probably a good fighter like people have said. The evidence kind of points to a made up history as to the origins of his art. Maybe he lists the same five families because of Wong's school/style because it was good marketing or they weren't really "family styles" but categories of technqies. When you read what each one represented it sounds more like this was the case with San Soo
http://www.realkungfusansoo.com/abouttheart.htm