Since I’m a simple-minded guy, here’s my simple way to get started. It works for me.
Here’s what I do:
1) Set the depth of the plunger so that the tip sits slightly to the left of the centerline.
2) At 10 yards shoot two bare shafts and two arrows. Raise or lower nocking point as needed to get arrows and shafts "impacting" at the same elevation. If bare shafts hit low, your nocking point is too high; hitting too high, your point is too low.(I don’t worry about nock high, low, R or L, at this point).
3) Once the nocking point is established, shoot the arrows and bare shafts again. If the bare shafts hit right, they are showing weak, and the tension needs to increase; if the bareshaft hit to the left, they show stiff and tension needs to be weakened.
Pretty simple huh. IMO, your arrows are too stiff and you “may” not be able to tune that much out with the plunger. (Scratching my head here) I'm at a bit of a loss to know why those arrows are showing weak.