Is he a T+ alibino? If you just put him in that enclosure, leave him alone. Your temps look good, but I'll be honest, that is a lot of space for a young blood/shortail. Does he poke his head out of his hide at night. If he does, that is when you should feed him. A few years ago, I started my first shortail, a sumatran, off in 36x28x18 vision cage. He never moved around and only stuck his head out of his hide at night to eat. I had to put the water dish next to the opening in his hide so he would drink. I got him out of that cage and into a rack, he was much more comfortable. Moved around at night, soaked in his water bowl etc. Mine at that age hardly ever sit on the heat either, only during shed or after a big feed. The older they get, the more comfortable they get, and the more mine move around. My oldest animals are in cages and they do really well. They are 5 years old however.