It seems to vary at times between authors, and I think too often it is taken for granted that they are about 1000 strong just because they are a Space Marine chapter. I am also a vet Space Wolf player, but I do not draw any artificial distinction between FW Space Wolves and Space Wolves drawn from any other source such as Krom Dragongaze, etc. 2 each against eldar, necrons, and Tyranids.