Help with leveling table

It should take a 3/4 inch open end wrench. Unless you have a machinist level you can only get it close. Anyways use a level and find the low spot. Raise that side up and you should be good. Sometimes, depending on the level of the table, its easier to take all of the legs to the lowest point and start all over.
Remember all 4 legs cant be low. In other words you shouldnt have to raise all 4 corners. If you do, then you done something wrong and should start all over again. Hope this helps

The only way to really level a table is to roll or shoot a ball in every direction and adjust the legs or shim it as you go. A table will read
level with a level and many times it's not level. Your eyesight will be better
than any level as far as a pool table goes!

If you don't have a starrett level then a ball will work as long as its a quality ball.Just look for patterns in the ball travel.

I like to use a laser level.

My table is in a house (pier and beam) that moves with changes in humidity. So, I have to re-shim it all the time.

The most sensitive part of a balls roll with respect to the level-ness of the table is "as it comes to a stop". So, place the CB at diamond 1 from corner pocket and roll a lag shot lengthwise. After contact, stoop down so you can place your eye on the line of ball roll. As the ball comes to a stop watch for movement sideways. Then check the opposite side, and then check it again from the other end.

If the ball rolls off differently from side to side, you have a piece of slate that is bowed. If the ball rolls off different end to end, you have a table flexed in torsion.

On my 8 foot table with Simonis 760 one piece (thickness) of typing paper is worth about 0.5mm of sideways motion (the long direction) as the ball comes to a stop. I crawl up under the side of table and lift it with my back while adding or subtracting a sheet of paper, then retest.

For the absolutely most accurate method of checking a table, get a glass mirror and a small marble or steel ball bearing. The mirror must be flat and free of adhesive or anything else on the back. Lay the mirror at various places on the table and then gently roll the marble or ball bearing on it. You will quickly see how the table rolls.

This method eliminates any error that might be caused by an out of round or off center weighted ball.

The mirror rick sounds like a great idea, just need to make sure it is perfectly flat.

I have seen digital levelers used for automotive, I know you can find one that you can use on a pool table too. Some of them are very very accurate.
I thought I saw a pic of where a team was setting up some tables and they put like a dozen levels on the table when they set it up.
You might try youtube, you might find some vids there.