The Rizzutos come in Canada from cattolica Eraclea in the 50s to control the heroin from Sicily to the us. Take control of Montreal kicking out the violi and the Calabrians in the 1970s.
His power was in a sort of federation between italian,biker and irish and black gangs for deal in drugs.
Niccolò and after his son Vito role on montreal but was a strange family more similar to the Outfit that to a sicilian crime family. Some say that the rizzuto fall because Vito made non italian and in sicilian doesn't accept this and killed joe bravo and the other guy. When vito was arrested and extradated in the us for the 3 capo murders in 1981, all the force first the Calabrians attacked and the war begin.

I think that with the time the rizzuto grow up by a single crew to a real family and the murder of Sciascia cuttted all the remaining ties.

For the exactly membership since nobody flip I say 50-60 made men not more and maybe 200 associates.