IMHO, it greatly depends on you and the individual horse. Do you have pictures to show the horse's conformation? Do you have pictures of you riding the horse? How balanced and fluid are you when you ride?
A person your size that is a good rider, I wouldn't hesitate to put on certain horses that only stand 14.2-14.3, because their conformation is suited to carrying heavier weights; their backs are short and strong, their barrels are large, they have big bones and feet, their chests and hips are wide-set, they have good muscle mass, etc.