You're wrong, though. The Cavaliers have a zero percent chance of beating the Warriors by going small. They have an insignificant, but still greater than zero, chance of beating them by going big. Cleveland can't threaten them by trying to "match their mobility," because their most "mobile" players, with the exception of LeBron James and Iman Shumpert, are also their worst defenders.
Cleveland's only chance is to go big, hope that Golden State has an off night, and get all the rebounds. They can't win any other way. You can't beat the Warriors unless you have athletic players with length, who can play both ends, and aren't stupid, and can play disciplined basketball. Basically, some kind of amalgamation of the Spurs, Hawks and Thunder.