The nature and mass of JCP's usually warrant overhead heating (or room heating) as opposed to floor heating.
CHE's are excellent heat sources, and reptiles do fantastic under them. You will need to touch-proof the CHE. A good way to do that is to cut and bend hardware cloth into the shape of a box and firmly attach the box around the CHE to the ceiling. Leave at least 1" space from any part of the CHE. The more space between the face of the emitter and the wire, the better. I think 3 inches is best.
Since JCP's have big heads, the hardware cloth can be as large as 1/2" squares if you want. The larger the space between wire the better as long as the snake can't get up into it. Put another way, the less obstruction between the CHE and the animal while still protecting the animal, the better.
The second choice for me would be infrared heat lamps. These do a fine job of heating and cost much less than a CHE. They do burn out sooner though, so you will need to replace them from time to time. CHE's last a long time. I have a few that are 5 years old and still work, though they haven't been on full blast all five years.
I've used 50 watt infrared bulbs with no wire cage to protect the animal. The bulb is very very hot but not damaging to flesh if touched very quickly. Still, a wire cage is recommended.
A word about heat panels: The advantage of heat panels is that the surface will not damage flesh if touched for a few seconds, and they heat a sizeable area without excessive wattage. You really should consider investing in those, and when you do, you will not need to replace them for perhaps 10 years. No wire cages neccessary.
An inverted, ceiling-mounted Kane heat mat makes a fine heat panel, but since they cost as much as a heat panel, it doesn't help your situation.
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Mark