Just try to do the inputs like you see in his video. It works. Just sit there for a couple of hours and practice it. I think I’ve gotten to the point where I can hit it about 90% in training mode. And I know when to try to throw it out and when not to during a match. With the lp version, when I mess up, I’m less likely to be punished than if I messed up doing the HK version. If I screw up my inputs, at most, I get a st.mp. I found that when I messed up the HK version, I would get st.HK which then can punish with another ball. But the most important part is that you have to pay attention to how you blocked the ball. If you block it late, it’s a lot harder to hit it with GH. If you blocked it early enough, you can tell that it hits you “deeper” so he doesn’t bounce quite as far away. I don’t bother trying it if I blocked it crouching. Like Renegade said, it’s mostly a timing issue. You want to take just a slight step forward after getting out of block stun and then hit lp~lp+mp. That way, even if you screwed up the kara, if you timed it right, you’ll still get them with regular GH. Baring you blocked the ball early while standing. That’s just how I do it. I’ve managed to use it quite effective in actual matches.
Oh, and using turbo/hacks to do cr.lk links is quite lame. Which in turn makes me hate this thread even more.