I have found that people who have trouble with the gizmo often over adjust it. When I am on the long string I adjust it one time to the deepest bend on a limb, make a full swipe of the limb I adjusted it to and then make a full swipe of the opposite limb with the same setting. I want both limbs bending the same and a single gizmo adjustment is the way to get headed in that direction.
I readjust my gizmo as I increase brace height but still use one setting for both limbs.
When I am at the shooting stage on a bows tillering, past the point of getting a legible mark with the gizmo for extra fine tillering adjustments, I eyeball the tiny gap differences and mark the slightly stiff spots with a pencil.