When it comes to hookah tobacco, there is no one-size-fits-all answer.
The amount of tobacco you'll need will depend on various factors, including the size of your hookah bowl, bowl packing method, and the type of tobacco you use.
The average bowl fits 15-20 grams of tobacco, while some bowls are meant for solo sessions and can only fit about 12 grams. A general rule of thumb is that after evenly spreading and leveling the shisha, it has to be approximately two millimeters below the bowl's rim so it would not touch the surface of the foil.
If you want to learn how to pack a hookah bowl, check this tutorial.
