Hmm good question. I watched a pat paralli (spelling?) thing on TV a while ago and he was on this tiny QH, wouldn't have been more than 15hh, with what I considered little legs, full western gear and himself. Now maybe the camera was adding a few kgs but he is by no means a little slip of a chap. He has to be about 6ft and a decent weight.
However no one bats a eyelash at that.
Now pop a lady of similar height and weight with the same gear and horse and it would be seen as cruel.
I understand QH are hardy, strong little things, I've ridden a friends one who carried me and the western gear without a hitch, I'm just saying, he looked bloody stupid atop this little mare and personally, I think he should have been on a bigger horse.
But I don't know much about him so I can't really judge.
My brother, who isn't over weight by any stretch of the imagenation, prefers riding the big drafts because he looks stupid on the smaller horses. He is quite tall and plays polo a bit and he really does look daft on the little polo ponies :P so I guess it's personal choice.
I am her eyes, she is my wings. I am her voice, she is my spirit. I am her human, she is my horse.