Well I've only had him about a day and a half now and over night he knocked my probe thermometer into his water dish so we were using that to verify the temp of the UTH (I also have a thermostat regulating that) and the cool end was a little cooler than I'd like when we were last able to check it before the drowning of my thermometer.. as for the bigger hide we are currently also working on getting him a larger tank because I feel he does not have enough room in his current setting with the water dish and hide theres not much room to wiggle around and I also feel that he's stressed due to the new setting.
Where you placed the thermostat probe? Maybe a photo from the setup can help digging out if something wrong with it.