yep, what everybody else said sounds right to me as well. I pump until the tip will not bend easily.
too little and the kite will fly funny, jellyfish, and have trouble relaunching. too much and it might explode on a tomahawk crash. smaller tubes need more pressure than larger tubes and smaller kites need more pressure because of smaller tubes and it is usually gustier when windier and the increased pressure can make the kite more stable. if in doubt a little more is usually better than a little less.
but don't over think it like we all have