I like 4 inch wheels on something like that. If there's room to maneuver, I prefer four wheels with two fixed on the rear, two swivels on the front. The swivels should have locsk on both the wheel turning AND to stop the swivel. Assuming the table is pretty wide (long), they can be affixed to the bottom corners. But on a narrow or small table, I always add some sort of wider base or outriggers to give a longer, wider base for stability when moving. 3 wheels will want to tip if you hit something on the floor, such as a cord or small bits of wood.
The more I do, the less I accomplish.