Does moving the rest to the left (away from the riser, as you said) make an arrow show weaker or stiffer?
I have a similar problem, but I am just on the other side - shooting 250's and they group left (too stiff)
Some places I see that if your arrows are grouping left, you move the strike plate AWAY from the riser, or make it thicker, and then some places say make it thinner, or move it TOWARD the riser. Adcock says both things in the same paragraph if you read it carefully.