Check to make sure your table top is not warped. Apron or no apron? And post pics.
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if they are on an angle, pick one and make a gauge to match the angle, match other legs up to the angle.
if it is a tiny amount and concrete floor, move it around some to see if they even out, slab could have some minor dips.
use a battery drill and set the clutch to about 5-6 to start, redo all screws till it ratchets, increase if needed for tightness.