Looks good! Hmm, I use a light dimmer for my UTH, it works fine. I aslo spent several days before hand measuring and marking to make sure it is reliable. You want the bottom of the warm side, without substrate, to feel slightly warm. if it feels hot to you it is broiling to a snake.

Leave him for a few days and don't mess with him. Buy a small rat, and after a few nights if he is out hunting, place it in the cage and supervise.