Looking good Paul, nice job on the jig. You apparently have a good eye for centering the drill to the blank.
One thing you could do to help would be to establish the front to back center as accurately as you can & then scribe a reference line directly onto the drill press table along the rear edge of the jig base. Then you could use the reference line to visually position the jig in the future, or clamp a block to the line to butt up against. Since centering left to right varies with the thickness of the blank, that would probably remain an "eyeball", unless you want to get more complicated using pre-made spacers for different blank thicknesses.
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