I tend to believe it’s usually counterproductive to do too much in-depth technical analysis on different market cap or sector indexes. Everything is so tightly correlated anyway, so differences often become a matter of analyzing noise. Looking at retracement ratios and trendlines on these instruments and trying to make market calls is, largely, an exercise in futility–you can often get better information from a solid analysis of a single index.
However, once you have derived a basic market call, sometimes it is most clear in a particular index. In this case, the Russell 2000 index (using the IWM here) shows the pattern most cleanly from a trade management perspective: the small parabolic exhaust above the parallel trendline, followed by a subsequent selloff and consolidation, sets the stage for a nice short entered on a weak close (or intraday.) Note also that we have been monitoring the R2k/S&P 500 spread; weakness there suggests more bang for your (short) buck in the midcaps compared to large caps, should the market sell off.