I have the caliper positioned 1/2 way between navel and solar plexus. The gap is set directly over the center line of the body. The two flows of heat generating, flow down both sides of the stomach. Focus on this, and it will go everywhere that you look inside your body.
Many of the energy producing effects happen between the chakras. Requires opening at least two of them at the same time.
Find this point on your body and then only touching it with a finger can produce the heat flow.