ok digital thermometer = good. those little analog ones - throw them out they're trash (much too inaccurate)
get yourself an accu-rite - its a digital thermometer/hygrometer (measures humidity). can get this at walmart, lowes or home depot for $12-$15.
& i imagine that hide box is a little big for him cuz i see him curled up in there and having a bunch of space...these guys like to feel hugged on all sides of their hides, my little girl has to practically squeeze into her hide boxes mostly after she's eaten but she curls up and sometimes the hide box ends up ontop of her and she's fine with that she still thinks she's "hiding". you'll also want another box on the cool side, preferrably identical to the one you have on the warm side so if your guy decides he wants to go cool off he has something else to hide in.
thats what i see...