I still have the same heating pad down there in the box. We've had a few cold spells here in Arizona - dipping into the low 30's for a few nights in a row - and I cover the tunnel entrance with a thick towel. It's quite a bit warmer inside his enclosure vs. outside. I'm pretty sure he's nestled deep down at the end of his burrow but at least there is a source of heat in the main box area for him. A couple weeks ago I didn't see Gilbert out & about for about 5 days so I ran a small space heater fan at the entrance aimed down the tunnel and sure enough, he came up to investigate and bask. Made sure he had a good meal of kale while he warmed up. It's been nearing 70 degrees in the afternoons now and he is out & about. He just eats my lawn and I supplement with kale and a few other things every now & then. I also just leave the heating pad plugged in around the clock when it's cold like this.
I've actually never weighed him - wish I did when I first adopted him. I'd estimate he's about 35 lbs from the times when I occasionally have to pick him up and relocate him when he's carrying the patio furniture around on his back! I'll have to get a scale and see what he truly weighs.
Well I gave him a quick warm rinse & scrub today. He weighs in at 33.5 lbs and his shell is about 20.5" front to back. Contrast the first picture of him today on the 16" X 16" patio tiles with the second picture of him on the same tiles in May 2014.