Everyone has their own strengths and weaknesses judging deer - I have to watch myself when deer are going away, they are skinny, they are in velvet or they don’t look right at me or away with ears fully out to the sides.
If that was a big bodied deer in the middle of cold weather in October his face would look much larger and filled out, making the rack seem smaller.
Not a lot of mass when velvet doesn’t appear real bulky - pretty skinny rack under there.
With his ears out flat it’s about even with the outside spread - a big deer will have his ear tips well inside the rack.
I think it also helps to develop an instant feel for the depth of the forks. That’s a simplistic way of saying tine length. With a one second view of a video or picture, you’ll already have a pretty good idea of his size based on that alone.
One year we found an honest 30” outside spread deer for my Texas buddy who had always dreamed of a timberline Wyoming buck…we had a few minutes to look him over and he had rather shallow forks and wouldn’t score high, but nice and wide so he took him opening morning.
What we didn’t expect, was the deer had either a birth defect or an old injury that caused one side of an otherwise perfectly symmetrical rack to point upward. From he center of his face to the left he would be a 31” deer, but if you only looked from center to the right he was only 27”. The actual width was 29” outside, so still a good deer.