Circumstances vary, but the general rule is to go high enough to clear ground turbulence, but fly low enough to maximize control and to look impressive. For us, that is usually between 100 and 150 feet. Leave the kite anchored and walk it down from the anchor point. This is easier if you use another strap and connect it to the line with a carabiner. If the wind is stronger, walk it down with two or more people.
Caution is good.
But the only way to get experience is to try it. And it really isn't that hard. Just go slow, be careful, and don't let a few crashes spoil your learning experience. A pilot kite is a stable kite, usually a parafoil, Sutton, or larger rokkaku, that is tied into the main kite and used to stabilize it. We fly pilots about 50-100 feet above the main kite and most people don't even notice that they are connected.