This followed me home today.

[Sunset Machine]

The grout should reduce vibration by making the base a little more solid and housekeeping chores are made easier. I'd rather not grout, mostly because I don't want to contend with grout stuck to the floor making pipe rollers difficult to use if I should want to move the thing. The reason they are leveled is so oil drains from the table properly and who knows, you might want to use a level in making a setup some day.