It's simple Mark.

Measure the width of the leading edge, at the point where a hinge is located, divide that measurement by 2. this number will be the depth of the hinge on the pin. Then Depending on how much throw you want, you more than likely will have to carve out a slot for the hinge. The trick is not removing too much so they look good.

The picture shown is the wrong way to do it.

Billy