I think that maybe the thread has gone a bit off topic(oh well)
The BT have at least 5000 to 6000, the SW i have no idea as to what there numbers are. and the DA well as the one guy said above, chapters combined would probably come some where near 6000 marines or stronger not counting recent deaths or recruts, so it could be weaker.
Actually discussing whether the Space Wolves are at Legion strength or not seems to be entirely on topic
I don't disagree that the Space Wolves are much larger than your standard Codex Chapter, just not any more than 2,000 absolute maximum.
Using the argument that the Chapter should be so much larger because the Fang is so vast is misleading- the Fang's internal structure is extensive because the Space Wolves Legion
required the space, it wasn't built after the second founding so the Chapter uses the space already manufactured.
Using your example you could extrapolate that the Ultramarines should still be at 250,000 because they have the facilities in Ultramar for that many Astartes...
random perculation of thought- the Ultramarines really
sacrificed themselves during the Heresy and especially during the Scourging in their efforts to hold the Imperium together- 9/10ths of the Legion perished. Don't believe me? The Ultramarines Legion have been stated as having 250,000 Astartes at their height, but during their 2nd founding they supposedly founded 23 primogenitor chapters, that's a drop in numbers of over 225,000 marines...and yet by the end of the Scourging the Ultramarines accounted for half of all the Astartes.
Heresy+Scourging= Astartes genocide