AO, the deltas drifting to the left is most likely a "too stiff" spine tuning issue or your release. Field points won't show it, but a broadhead will. Try them mounted horizontally, this may help some, but to really fix the issue try a heavier head, 160+ gr, or a lower spine. You probably aren't far off, as the fletching is getting them straight after 20 yds. Fletch wing and rotation won't give you this.
Sharpening is a learned technique, so find someone who can walk you thru it. Raising a bur, consistent angle and light pressure are three keys. There is a TruAngle kit in the classifieds; Zwickeys will shave hair right off the files.
Good luck!