Since you live in an area where it gets rather cold in winter, I'd go with the heat lamp in addition to the pad, only turning on the lamp when things get chilly though. Make sure you put in a nice thick layer of substrate - they LOVE burrowing, and a couple different substrates that work great for this are aspen and a lovely thing called EcoEarth (compressed coconut ... husks I think). The catch with ecoearth is you have to make sure it's not too wet when you put it in. You want it to be nice and dry and crumbly, and what works for me is I just keep the area under the water bowl wet (gonna get wet anyway, right?) so that he has a place to go should he want to get cool and damp without getting wet (like when he's going into shed).
You might actually be able to bump Theo up to fuzzies. Mine (Tetris) is about as long as Theo, and he chows down fuzzies without a hitch. If you're worried about the fuzzies being too big (more than 1.5 times the biggest part of his body), try giving Theo a pinkie every five days instead of seven. If you do try fuzzies, be prepared for the first time to take a while, and for it to take longer to digest.
Temperature - as long as you can get one side to be about 85 degrees, maybe even 90 (depending on how big your tank is), then the rest of the tank will gradually cool down to about room temperature. If you have a small tank (10 gallon), aim for 85 on the hot side, because if it gets too much hotter the whole tank heats up above the snake's comfort level. Measure the temperature about an inch above the substrate (snake level) and if it's still low then turn on the heat lamp for a few hours in the morning. At night things can drop to 65, but only as long as he has those nice toasty warm hours from morning to about midafternoon.
Brumating is essentially hibernation, and as long as you keep your king warm you don't have to worry about it. It triggers breeding once they come out of it.
Hope that helps!
~jenny
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1.2 normal ball pythons (Cindy, Darwin, and Periscope)
0.0.1 california kingsnake (Tetris)
0.2 rescue chinese water dragons
1.0 rex rat (Scurvy)
1.0 gerbil (Yerbul)
0.1 bunny (Spazz)
1.1 betta fishes (Vicious and Killer)
2.2 great danes (Shasta, Odysseus, Merlot, and Watson)
1.0 fat fuzzy mutt (Smokey)
1.1 cats (Thidwick and Turtle)
2.0 horses (Buddy and Sam)
1.0 goat (Billy Jack)
1.25 chickens (Ugly the rooster and his harem)
"God is a comedian playing to an audience too afraid to laugh." - Voltaire