i have my full set up and pictures in my profile if you want to see how i have things set up. it looks like my enclosure is a little bit bigger than yours but you'll at least get an idea. (i actually have 3 probe thermometers, but i'm lazy and dont want to move them around. 2 would be perfectly fine.) we probably need to address your ubv too, but that could be another entire thread!
I would get two digital probe thermometer-s they are the most accurate for basking temps- place probe where he sits for basking you want 95-100 for adult juvie dragon