Hmm, there's a bit of a problem, though. That collapse animation, more often than not, does not have any clsns. So you wouldn't be able to hit anyone after they get crumpled.
I think it would be best if you used a custom gethit animation, using required gethits. Like this:
Clsn2Default: 1
Clsn2[0] = -20, -60, 20, 0
5000,20, 0,0, 40
5000,10, 0,0, 6
5000,0, 0,0, 6
Clsn2Default: 1
Clsn2[0] = -20, -40, 20, 0
5020,0, 0,0, 6
5020,10, 0,0, 6
5020,20, 0,0, 6
Clsn2Default: 1
Clsn2[0] = -30, -20, 30, 0
5040,0, 0,0, 6
5040,10, 0,0, -1
This ensures the opponent can be hit, and it looks decent enough.
It would be better if there was a standard that specifically requires hitboxes, since there's no way of knowing if character x's 5950 will have them. I'll come up with one, and add it to the optional animation standards thread.