Assuming you otherwise have your ET arm aligned correctly to the surface of your platter (parallel across the surface, post locked in vertical position, etc.), leveling the arm is best done by leveling the turntable:
...Lift the cueing lever up (to make sure the stylus doesn't inadvertantly contact the surface of the platter while you do the next steps)
...take a piece of mortite or plumbers putty and place it on the counterweight to bring the arm into a neutral balance
...once in a neutral balance, the arm will slide freely: use is as your "bubble level" to level your turntable side-to-side over the travel of the tonearm's spindle.
As an alternative, if you have a single-sided pressing of an LP with one perfectly smooth side (some are not smooth), with the LP smooth-side up and spinning, you can set the tonearm done on the LP surface and observe which direction the arm skates. Then adjust. The neutral balance method above is more accurate.
If you're trying to level the arm by loosening and adjusting the post, you will find this a maddening process. The adjustments at the post should be used to get the geometry of the tonearm to platter set correctly, but not to level the arm.
.
...Lift the cueing lever up (to make sure the stylus doesn't inadvertantly contact the surface of the platter while you do the next steps)
...take a piece of mortite or plumbers putty and place it on the counterweight to bring the arm into a neutral balance
...once in a neutral balance, the arm will slide freely: use is as your "bubble level" to level your turntable side-to-side over the travel of the tonearm's spindle.
As an alternative, if you have a single-sided pressing of an LP with one perfectly smooth side (some are not smooth), with the LP smooth-side up and spinning, you can set the tonearm done on the LP surface and observe which direction the arm skates. Then adjust. The neutral balance method above is more accurate.
If you're trying to level the arm by loosening and adjusting the post, you will find this a maddening process. The adjustments at the post should be used to get the geometry of the tonearm to platter set correctly, but not to level the arm.
.