It's a bit simpler than your own answer. Your base 3 wasn't a big crack in either % drop or angle/speed of drop. After that little shelf started turning down, that's when I would have started thinking the move down might hit that base 2, therefore using base 2 as my base and buying in below base 2 with a sell near that second shelf in that second circle you drew to the right of what you call your base 3.