I can make one suggestion that may help. If you are just trying to get the pin dialed in shoot at a line, not a dot. Draw a line from left to right (or right to left I guess) across your target. Then just aim at that line. Don't worry about aiming left or right or where the arrow hits. Just try to keep the pin on the line.

It is much easier for you brain to focus on one axis instead of two. This may help you out.

Not saying it will help you with your groups, but it may make it easier to set your pins.

Paul