Originally Posted by 48Sam
The lugs holding the wheel adapters MUST be flush with the spacer. They cannot exceed the spacer width, otherwise they will interfere with the wheels when bolted on.
Here are mine, they are flush:
The nuts on the adapter must not interfere with the wheels, but strictly speaking they may stick out with certain wheels. Many wheels have cavities on the mounting surface of the wheels in between the holes (to deal with shrinkage issues in the casting process), for example:
I don't remember if JK wheels are like this and can't find pictures of them, but if the wheels you are putting on have these recesses, you MAY be able to get away with the lug nuts protruding a little. The wheel MUST mount flat to the adapter though.