For some reason I thought Nelson was older. Very cool! My tort was really gaining weight his first year, year and a half, and now he's gaining about the same number of grams per week/month except he weighs more. Slow and steady is the way to go so I wouldn't worry about it. I do let my tort eat as much as he wants though. He's been weird lately with his schedule and getting up late and then being unhappy when his light goes off and he still wants to be up!
Yeah Nelson isn't a big burrower. Usually he just sleeps on the surface under his hide.
And Whitney, I love that you have a Russian named Carl! My dog's name is Carl