You can't really adjust the hover height. You can increase the pressure under the craft, and that will raise the height a little bit, but it you get more than an inch or two off the ground, the craft will "roll" off the cushion of air, hit the ground, and then air up again.

Not a problem on ground, but could be a major problem on water. The best setup would be for it to be off the ground just enough to where it isn't touching, so its just gliding on air.