I understand you being skeptical since this was my first post out of the blue. I've been registered and have been lurking since late March, I just don't post. This just was just an interesting thing I wanted to try since you gave me the idea and figured I may as well post.
Yeah, it was annoying to do. I only got it 3 times in like, an hour of attempts. It seems doable since I see a lot of players in vids do the cl.c f+a after command grabbing someone. But, doing it 4 times with stricter timing seems rough. I probably wouldn't do it in real games just for an extra 20 or so damage over the far d, rekka, dp, grab loops.
With it being optimal or not, I think it's close if not already good. I don't think there's enough time to get another rep. At most, you'd get an extra rekka before the neomax/super.
EDIT: Yep, you can get a fireball. cl.c, f+a, HD, (cl.c, dp+c (2) DC hcb,f+p)x4, far d, qcf+c MC neomax is 754. And nope, no 5th rep.