DaBoyz will need to halt the carnage in the tech sector to turn the broad averages around, but it’s hard to imagine which stock they might call on to lead the turn. Shares are in a delicate way, and even a small grey cloud on the news horizon could kill a nascent rally. Our key bellwether, AMZN, looks as though it will have to fall at least another 2.5%, to around 489, before it finds decent traction. If this happens quickly and within an hour or so of the opening bell, that could provide the emetic needed to set up a short squeeze.  But if index futures open relatively flat look out below, since that could embolden bears to go for the gusto.