Years ago, I've been exploring single hand card manipulations and somehow came across to something that looks like Twitch. I don't have Twitch but if my method was just somehow similar with Eric's, then you can read on.
As with other single card moves, there is always some difficult part in getting the secret move(s) correctly. For example, when I was learning Clipshift, at first I wasn't able to get the cards to square up perfectly. I think it's just the same here in Twitch (I mean, the one I experimented with years ago). Also, angles could not always be so perfect. You might have tried Snap change and find that it doesn't always work quite well in a big crowd.
Twitch really looks good and I think if you really get into it, you'll get it down soon (if you purchased it).
Well, that's just what I think. There might be other members to reply to this post of yours who might give you better answers than mine.