Just a quick update for anyone following. I've been handling him for about 15 minutes everyday since I've had him. He seems to start looking for places to go after that, so I figure that's his way of saying I've had enough. He's still shown no signs of aggression and is quite a sweetheart, he's actually coiled around my neck as a type this. I got a weight on him this morning, he only weighs 341 grams. I'm finding it really hard to believe he's as old as I was told, he's just so small. Maybe chronic malnourishment can stunt growth that severely? I'm just finding it hard to believe he's at least 3 years old, but the person I got him from could just he fibbing to get rid of him.
Remember to avoid handling for 2 days after he has a meal, and over-handling also causes them stress (which you will know if he starts refusing his meals).