what size tub are you housing him in? I keep my larger males in 96qt rubbermaids and use 11'' flexwatt on one side. Just going off what you said your heat pad is probably just too small. Winters here in NY get pretty cold and I use an oil based heater in my snake room. When I was just keeping a few snakes I used ceramic heat emitters but I was also using glass... Those things get way too hot to use with a plastic tub. What you could do is have two pieces of flex watt hooked up to two separate thermostats... one set to 92ish and the other 80ish. This will give them a warm side/cool side gradient and also might help boost your ambient temps. Plastic is much better than glass at holding the heat in so I think thats your best shot.