I weigh the same as you and mine is fine with me. I only go 20mins because of my physical problems, but he is away at school at the moment and the adult trainer is the same weight and she is doing hour long hacks with a little trot and he is coping so well so she went without his trainers on today (cavello boots) and his feet were fine, so all this is without shoes. He still tanks off with me in gallop too, which is why he has been sent to get slowed down.