Nice chart! I like your analysis on how the measured move becomes support. Currently, we have three supports near today's close price: (1) support at 190.56 from the measured move of the bull flag, (2) EMA 50 at 188.80 (almost touched by today's low at 189.03), and (3) 0.5 Fib level at 187.24. Therefore, a confluence area for support is formed. Let's see how well it works tomorrow.
This would be a good low risk trade given the prior strength, My system suggest that the price has a high chance of reversal to the upside. I would consider buying if the price reverse up on up volume and the up volume is greater than the up volume 10 days ago.