Ditch the undertank heater it is a waste. Go with an overhead heater...ceramic bulb or a night bulb. Use one basking spot on one side of the tank between 90-100 and leave the rest of the tank room temp. this way he can regulate his own temp. Always a good idea to have a branch or something that is close to the basking spot so he can move up and down it to regulate his body temp. I have my basking light on a timer to go off with the lights...its not 100 degrees in the desert 24/7 it actually gets cool in the desert at night. take that into consideration.
As far as UV...you need it and its good that you ordered it. you still have to suppliment him with calcium but he also needs UV light to convert that calcium into what his body can use.
As far as feeding, a 5"er should be able to take some 1/2 inchers...pinheads would work too i guess but their so tiny. Small meal worms and lots of veggies....My guy loves meal worms and jumps at them when i put them in. As far as vegies go...No lettuce! Feed a staple of any type of green. Kale, collard, mustard greens are all good. My guy also loves Yellow squash and it brings out a nice yellow color in him too. He picks it out of the grens when i add it to his "salad". Other fruits and veggies are apples, grapes, banana's, carrots..etc the list goes on! Also make sure you have water in there for him.
If he has been recently moved he might still be in shock from the scenery change..leave him alone for a day or to...leave food in there and im sure he will start eating. Just dont bother him, let him get used to his surroundings.
As a last resort you can buy a appetite stimulant at the LPS..I had to use it once on my breeding female it got her eating quick.
On a side note, I used to breed dragons. Ive had over 150 in my house at one time and dragons are very good eaters from the minute their born untill they die If he doesnt eat soon you will have to force feed or possibly take him to a vet to make sure there is nothing wrong with him.
HTH's
