Where to catch the falling knife?

So it's dropped a fair bit since I started writing this post, but needless to say, it would be best to wait and see something technical before a reasonable buy on a pull back could be justified. Looking at the weekly time frame, I'd expect a bounce from about the 115 level, so any bounce could then be judged on its own merits, if it's technical and showing signs of resuming back to the upside, then better to buy on a pull back from there (similar to the GBP chart), in what would be a lower time frame wave 2, than when it could just as easily keep dropping.