IF you bought Monday's close price on SPY you would sell Tuesday's open price. After hours trading was not included in the study as it used the SPX ETF:SPY to trade that is tradable like a stock in any trading account.
The NG chart and comments about the snap back to the 20ema and broken channel resistance was just an observation certainly not an encouragement to get long for the snap back. But I just said if short you can see by looking at the chart that price is like being attached to a rubber band and when 'stretched' away from the 20ema does snap back each time. So 'if short' one could consider exiting and re-shorting at the 20ema and resistance point. Not a lot of price action to trade so anyone trading it must be nimble and grab what they can.
As far as Gold goes price is still hanging in there at the main support 'area'. A Friday close would be more important. Price is still above the Sept lows that saw price do the same thing. Still not oversold technically though as I've been watching for a spot to get long and don't see the set up I'm looking for just yet. Doesn't cost anything to watch. Haligonian mentioned the extreme bearish sentiment on Gold the other day which suggests the selloff could be brief. Doesn't mean it can't plunge 1st but likely brief. The triangle breakdown does project more downside too.