I don't know, he really reminds me of one horse I know, he's a Clyde/TB cross, and looks a lot like your guy. His name is Cooper, he's 16.3. He's a bit slimmer, but he's only coming 5, so he's still growing.
He is so gorgeous though! Can't wait to see what he can do with time! And thank you for still using a snaffle on him, even XC. I've seen a lot of people that have big horses, not necessarily strong or spirited, just big, who put them in all sorts of contraptions for "control" when they don't even need it. :/