@ OP- You could get away with just the heat bulb only and forego the uth. I do add a uth with my CHEs in the winter months though just for surface warmth. You may also have better luck feeding your critter after dark. If he doesn't strike at the prey just leave it for a few hours or overnight even.
@ Valyrian- The OP indicated they were using a uth so I was only commenting on uth probe placement. I do agree with you that probe placement for a CHE or RHP would be different. I try to avoid using terms like should or shouldn't because they're subjective. As with most things, including heating reptile enclosures, there are multiple ways to achieve a desired result. I keep mostly pythons and colubrids. Some are terrestrial and the others are semi-arboreal. I use UTHs and CHEs effectively but I still think RHPs are the most efficient heating source. My new enclosures will have RHPs but my tubs, tanks, and other pvc enclosures all have their temps and humidity dialed in fairly precisely. It doesn't matter how you heat them just that you give them the proper temps and humidity which you can do in a variety of ways.
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